Leigh Steinberg stepped onto the football field at Southern Methodist University under a cloudy Texas sky. At events he hosts — like his gigantic annual Super Bowl bash — Steinberg, a sports agent, is accustomed to parading around like a presidential candidate, working the crowd with a boyish smile and a pinstripe suit. On the Dallas campus last March, in his sweatshirt and baggy bluejeans, Steinberg looked more like a guy at the local horse track. He riffled through a booklet of notes and popped a stick of Nicorette into his mouth. His client, the quarterback Garrett Gilbert, was the one who had to put on a show in front of more than 30 N.F.L. scouts, but Steinberg’s own prospects were also being tested.

The most fraught time of year was underway for Steinberg, and it had begun, as it does annually, a couple of months earlier, when the calendar turns over. While the N.F.L. season is peaking as it approaches the Super Bowl, agents like Steinberg are engaged in a shadow war with one another, trying to sign new clients from the latest crop of college talent. Then they stage-manage these clients through what Steinberg calls the second season for prospective draftees, a gantlet of auditions that includes private meetings and workouts, collegiate all-star games and the weeklong N.F.L. combine, where would-be pros showcase their skills and physical assets. At “pro days” like the one at S.M.U., college players go through drills at their home schools for N.F.L. scouts.

As recently as the late 1990s, Steinberg wouldn’t have bothered with someone like Gilbert, projected to be a late-round pick in the N.F.L. draft, held every spring. Back then Steinberg was the archetype of the football “superagent” — the man who represented eight No. 1 picks in the N.F.L. draft, the negotiator who secured huge contracts for his clients, the self-promoting white knight whom the director Cameron Crowe shadowed in preparation for his movie “Jerry Maguire.” Steinberg befriended movie stars, chatted up presidents, had his wedding featured on “Lifestyles of the Rich and Famous.” His net worth soared as high as $75 million. “He made it sexy to be an agent,” as another agent, Jason Chayut, of Sportstars, put it to me.

But over the first decade of the new millennium, Steinberg flamed out as spectacularly as he rose. His agency broke up. His former colleagues fought with him in court. He went bankrupt and was divorced, struggled with his sons’ medical problems and his father’s death. In 2010, he was living in his parents’ house, an alcoholic with no players as clients.

Now Steinberg was attempting a return to the game. Sober since 2010, he had just released his autobiography, “The Agent,” been recertified as an agent and opened a new sports agency — Gilbert was his first and only client. Like Steinberg, Gilbert was another fallen star. He led his high school to two consecutive Texas state championships and passed for more yards than any other Texas high-school quarterback before him. But his career tanked at the University of Texas, and after losing his starter’s job one game into his junior year there, Gilbert transferred to S.M.U., where he flourished at last as a collegian, setting school passing records in his final year.

If Steinberg was at all apprehensive about introducing Gilbert to the N.F.L. — and reintroducing himself, at age 65 — he was reassured to see a large turnout at Gilbert’s pro day, one that included plenty of familiar faces. The clipboard-toting men milling around the S.M.U. field included the former Steinberg clients Bill Musgrave and Wade Wilson, the quarterbacks coaches for the Philadelphia Eagles and Dallas Cowboys respectively. At around 10 a.m., Gilbert strode out to a giant red mustang, painted onto the grass at midfield, and began to throw. His receivers ran hitches, slants and curls; they sprinted all the way to the end zone as Gilbert lofted passes their way. He was whisper-close to perfect, completing 85 of 88 throws. One scout, who had just attended the pro day of the highly regarded prospect Johnny Manziel, confided to me, “I wouldn’t say that Johnny’s performance was any better than Garrett’s.”

Several weeks later, on May 10, Steinberg rang the doorbell of a large house in a tree-shaded cul-de-sac near Austin. The tall, gray-haired man who answered was Gale Gilbert, Garrett’s father; Steinberg had been his agent, too, back when Gale was a backup quarterback in the N.F.L., from 1985 to 1995. Gale led Steinberg into the living room, where everyone — Garrett, his mom, his brother, his girlfriend and several high-school friends — had gathered in front of an enormous television screen mounted above the fireplace. The late rounds of the N.F.L. draft were set to begin.

Like a student cramming for finals, Steinberg put on his glasses and chugged Diet Dr Pepper. Every few minutes brought another dose of bad news as a name was called on TV that wasn’t Garrett’s. Then, midway through the afternoon, Garrett got a call on his cellphone, followed minutes later by the news on TV: with the next-to-last pick of the sixth round, the St. Louis Rams had chosen Garrett Gilbert. The quarterback hugged his cheering parents and friends, and then Steinberg. “We are both in the midst of a comeback story,” Gilbert told me earlier. “My career, his career — we are sort of dependent on one another.”

A fallen agent trying to rebuild his career by starting with a single quarterback, that player struggling to win the love of a heartless N.F.L. — it sounds suspiciously like the plot of a “Jerry Maguire” sequel, but Steinberg insists that Gilbert is only the tip of the spear. Steinberg Sports & Entertainment, to hear Steinberg tell it, is abuzz with projects: discussions with television and movie producers. Client recruiting, corporate consulting and philanthropy. Television and radio appearances by the hundred. As was the case when Steinberg was in his prime, the client he most zealously represents is himself. The cycle of ego, ambition and adulation was accelerating once more, and I couldn’t tell if it would lead him back to greatness or cause him to crash again.

In a profession known for con artists, suck-ups and jerks, Steinberg always marketed himself as the ultimate Mr. Nice. The typical player’s representative was a slick hustler in a suit, but Steinberg, who began working as an agent in 1975, sported denim shorts and boat shoes. “He was a very laid-back guy, as California as you could be,” says Warren Moon, the retired quarterback and a member of the Pro Football Hall of Fame. Steinberg told his clients that they could leverage their popularity — and wealth — by contributing to their colleges, high schools and communities. They could speak out against bullying, domestic violence or drug abuse. “Most of his players have become stewards in their communities, and Leigh initiated a lot of that, if not all of it,” says Ray Childress, a five-time Pro Bowl selection as a defensive lineman and a former client of Steinberg’s. Steinberg himself contributed to philanthropies. He advocated for incorporating green technologies into sports facilities and organized panels of neurologists to discuss football’s concussion risk back in the mid-1990s, long before the issue was a mainstream concern. “He genuinely cared about more than just the money,” says the onetime client and former Miami Dolphins running back Ricky Williams.

The notion of Steinberg as “the Choirboy Agent,” as a headline once put it, wasn’t inaccurate, but it was apparently incomplete. The facade cracked in 2001, when his business associates, led by the agents David Dunn and Brian Murphy, split off and took more than half the agency’s clients with them. Steinberg sued for breach of contract, and the ex-colleagues fought back, soiling the choirboy’s robes in the process. Court filings and testimony presented Steinberg as a cad who licked the faces of two female employees; a drunk whose binges embarrassed premier clients; an erratic manager who once grabbed a female employee by the arms and shook her until she cried. The most damning accusation was that the supposed superagent, captivated by his own celebrity, was barely even an agent anymore. Murphy characterized Steinberg’s efforts to land new clients as “dysfunctional” while existing clients were neglected. “He simply signs them and never sees them again,” Murphy claimed.

A jury awarded Steinberg nearly $45 million (including $22 million in punitive damages), but on appeal the decision was sent back to a lower court, and the case was eventually settled out of court. What Steinberg calls “the fall” was now speeding up. He drank more, worked less and cycled in and out of rehab. The client roster dwindled. “Multiple huge opportunities” still poured into his agency, says David Meltzer, who worked for Steinberg from 2008 to 2010, “but because of his alcoholism, he couldn’t really execute on any of it.” On March 20, 2010, Steinberg chugged a bottle of vodka, intending to be drunk enough to be admitted to a detox facility — but was turned away because it didn’t have an available bed. This, finally, was the nadir. Steinberg says that he checked into a halfway house for recovering alcoholics, and with the help of a 12-step program (he still attends meetings twice a week), he has not taken a drink since.

These days Steinberg makes it clear that he is ready to return to the earlier, happier narrative of his life. “The story of my fall has been done to death,” he once snapped at me. “What about the other 30 years when we were doing great?”

The office suite of Steinberg Sports & Entertainment sits beside the bay in Newport Beach, close enough to the water that you could open a window and toss a Frisbee to one of the paddleboarders gliding by. Photographs on the walls pay homage to Steinberg in his former splendor: the grinning agent with star quarterback clients like Warren Moon and Steve Young; with Tom Cruise and Julia Roberts. When I visited in September, Steinberg sat tilted behind his desk in full casual mode: running shoes, belly extending out over jeans and a wad of tobacco tucked under his lip.

Chris Cabott, a 35-year-old agent and the chief operating officer of Steinberg’s company, sat on the other side of the desk with Steinberg’s 23-year-old son, Matt. They were hunting for new clients. N.C.A.A. rules restrict collegiate athletes from committing to agents, and some schools even forbid players to talk to agents, until the regular season is over, so the strategy was to court players’ entourages instead, sussing out the comparative influences of family members, friends and coaches. An agent named Ted Marchibroda Jr. had been doing much of the legwork, and Steinberg got him on the line for a conference-call update.

The first player on Marchibroda’s list was an offensive tackle whose family was from the Southwest. “His dad will love talking to you about players you have represented from Arizona,” Marchibroda said. The second player was a quarterback, and Marchibroda had already met his mother, a flight attendant going through a divorce. The mom would strongly influence her son’s choice of an agent, Marchibroda said, and he didn’t want to sour his relationship with her by contacting the dad as well. Next up was a defensive lineman; Marchibroda had spent two hours at his apartment and come away impressed. Unscrupulous agents frequently bribe players, but the lineman’s décor was austere — three chairs, no table or couch. “He is on the up and up,” Marchibroda said. “I don’t think anyone is doing anything financially for him.”

After hanging up with Marchibroda, Steinberg called the father of a college quarterback who was off to a hot start in his senior season. They bantered about the father’s work in real estate, and then Steinberg made a breezy but impressive pitch for himself. “I’ve been representing players for 40 years,” he said. “There was one weekend where I was representing half of the starting quarterbacks in the N.F.L.”

Scoring a top recruit was going to be difficult. Players often evaluate agents based on their latest blockbuster contracts — and Steinberg’s deals from the 1980s and 1990s no longer look so grand. “The numbers pale in comparison to what is going on today,” the agent Jason Chayut told me. Another element of the traditional Steinberg sell — his concern for the players themselves, not just their paydays — might not resonate as much now, either, with so much more money in the game. “The kind of athlete that was a good fit with Leigh has started to become an endangered species in the N.F.L.,” his former client Ricky Williams claims.

But Steinberg insisted to me that his brand still had appeal. “We are getting flooded with calls,” he said, from football players and also mixed-martial-arts fighters, Nascar drivers, baseball and basketball players and even a professional poker player. In the spring, Steinberg flew to Las Vegas to talk to Floyd Mayweather Jr. after a fight. All the same, by early September, at the start of the current N.F.L. season, Steinberg still had no other clients besides Gilbert.

Maybe he was being too picky. His son Matt suggested that they call back some less prestigious but “hot to trot” prospects — projected lower-round N.F.L. draft picks, plus coaches and sportscasters who had contacted the agency. Steinberg resisted. “I have just wanted to make it where the first thing we do is something dramatic,” he told Matt.

“I think you have to start somewhere,” Matt quietly replied. A certain sportscaster had “reached out to us, so the least we could do is call him back.” Reluctantly, Steinberg picked up the phone and dialed.

When I asked Steinberg how someone so recently on the skids could now be flush with opportunities, the agent responded: “The world didn’t go away from me. I went away from the world.” I’d heard this sound bite so many times that I was ready to ignore it again — but then I realized that it encapsulated his entire view of why he had fallen, and why he would rise again. Steinberg’s narrative is that he was assailed by outrageous misfortune beyond his control: his colleagues’ desertion, his father’s death. In his view, he had electively abused alcohol to escape from these problems. As such, success was like a romantic partner he had dumped, and now that he was sober and ready to reconcile, she would surely rush back into his arms.

An alternate way of looking at things is that booze and bad luck weren’t entirely responsible for his undoing. The core grievance of his ex-colleagues, who did not respond to my requests for comment, seemed to be that Steinberg, spread too thin with special projects and intoxicated by fame, lost touch with the essence of his role as a sports agent. But Steinberg called it “revisionist history” to find fault with a period in his life when he was so successful, and he bristled at my hinting that similar criticisms might be applicable now.

But the old Steinberg as portrayed by his critics — the one with his fingers in uncountable pots, the one who spent so much time nurturing his celebrity — bears some uncomfortable similarities to the Steinberg I was seeing. After the recruitment calls, Steinberg and Cabott spent an hour on the phone with the publishers of an online magazine that would soon be spreading the gospel according to Leigh, everything from negotiating tips to Steinberg’s views on combating climate change. In another call, the agents talked with an entrepreneur trying to develop Steinberg Analytics, a data-crunching methodology to predict athletic performance. Looking weary, Steinberg sipped a performance-enhancing sports drink — not yet on the market, from a company for which he was consulting — mysteriously identified as BEVERAGE 4.

Steinberg’s list of projects also included writing a sports column for Forbes.com, trying to sell a new book he had written about parenting child athletes and hosting a radio show for Yahoo. He had been giving an unrelenting stream of radio and television interviews about his career and also about hot-button issues in sports. He was advising a company developing a drug to treat concussions and talking with a helmet maker hoping to prevent them. And later in the fall, he would host his first Agent Academy, a daylong seminar for aspiring Steinbergs. Many of these projects might not pan out, he conceded. Some, like his environmental Sporting Green Alliance, seemed to exist largely inside his own head. But Steinberg said that you never knew which venture would turn into the next Athletes Direct, a promotional website he helped start in the 1990s for $200,000 — and sold a few years later for $20 million.

In midspring I watched as he stepped to the front of a classroom at California State University, Sacramento, one of the final stops on a country-crossing book tour for “The Agent.” Smiling and gesturing with the polished authority of a politician, he started his stump speech. It told the feel-good story of an accidental agent, a socially conscious U.C.-Berkeley grad who had stumbled into the profession as an unlikely way to make the world a better place. The uplifting material certainly played well in Sacramento. The college kids were barely out of kindergarten when Steinberg’s fame peaked, but when he finished speaking, the autograph-seeking students mobbed him.

As the current N.F.L. season unfolded, Steinberg’s client, Garrett Gilbert, had a mixed run. His preseason play was middling, and in late October the Rams cut him. In December, though, Gilbert was signed to the practice squad of the New England Patriots. The Patriots were actually playoff-bound, meaning Gilbert’s season would be extended, and he would get some tutelage under two of the sharpest minds in football: the head coach Bill Belichick and the quarterback Tom Brady. “So that story has a happy ending,” Steinberg said.

By early this month, Steinberg had signed three new late-round prospects — Khari Lee, a tight end from Bowie State; Taylor Heinicke, a quarterback from Old Dominion; and Ben Beckwith, an offensive guard from Mississippi State. Success begets success in agenting, and Steinberg still hoped to land “one top player,” he said. “That is my goal.” Asked how he felt about his chances, however, Steinberg was candid. “Unsettled,” he said.

Even if Steinberg never signs another top-tier prospect, he would still have one client to keep him endlessly busy — himself. Back in September, I drove with Steinberg to Beverly Hills, where he had a meeting with two Hollywood producers, George Furla and Martin Blencowe. The meeting was at Spago, and on the way in Steinberg bumped into the restaurant’s celebrity chef, Wolfgang Puck. Back in the 1980s, each was featured in a television commercial for Pacific Bell. “America’s superagent!” Puck said. “How is the comeback going?”

The two producers, sitting in Spago’s white-tablecloth dining room, looked as if they’d just wandered over from the gym, Blencowe in a blue polo shirt and Furla in a black T-shirt and shorts. Everyone talked football during the appetizers, and then, midway through the main course, Steinberg made his pitch. “Let’s talk about ‘America’s Quarterback,’ ” the agent said.

The idea was for a reality television show like “American Idol,” except that instead of searching for a new pop star, the object was to discover a pro-caliber quarterback. First you’d have tryouts with the requisite humorous outtakes, Steinberg said. “Then you bring the top 12 players out here.” He would train them “the same way we would if they were going into the draft.” A sports agent would oversee the prep work — chalk talks, on-field drills, character tests, the works. A panel of all-star N.F.L. players and coaches would eliminate a quarterback each week until there was only one left, and his prize would be a guaranteed spot in an N.F.L. team minicamp.

Blencowe loved the idea. “The only thing we have to do is find the right agent,” he said, laughing as he looked right at Steinberg.

Reality-show star would be a natural role for Steinberg, who long ago realized that he could make a living not only as an actual sports agent but also as someone famous for being a sports agent — similar to how Donald Trump has profitably played the ultimate American tycoon on “The Apprentice.” Furla, who sat stonily through Steinberg’s pitch, finally spoke up. “I don’t see how that cannot be a big show,” he said, nodding.

The meal wrapped up, and everyone stood to say goodbye. Steinberg was the one courting favor, but the producers did what star-struck people seemed to do everywhere around him. Blencowe handed me his cellphone, and then he and Furla stood on either side of the agent. The real-life Jerry Maguire was in the house, and the two producers wanted a picture.