Tom Brady’s football career traced an arc that bordered on mythical, ascending from sixth-round N.F.L. draft pick to seven-time Super Bowl champion quarterback and global celebrity. And, after more than two decades of unparalleled brilliance in his sport, it has ended.

The retirement announcement by Brady, who once said that he would leave football only when his performance began to decline, comes as he is, even at age 44, still clearly among the best in his sport.

Tom Brady of the Tampa Bay Buccaneers is retiring from football. Doug Mills/The New York Times

In his 22nd season, he led the league in passing yards (5,316), completions (485) and touchdowns (43) for the Tampa Bay Buccaneers, who lost in the divisional round of the N.F.C. playoffs to the Los Angeles Rams.

Brady’s official declaration came three days after ESPN reported his departure, inciting a frenzy that was initially denied by his father, Tom Brady Sr., and his agent, Don Yee, who in a statement said Brady alone would announce the details of his future plans.

Brady had for years asserted that he wanted to play until he was 45 years old, But on his “Let’s Go!” podcast with Jim Gray in late January, he spoke about spending more time with his wife, the supermodel Gisele Bündchen, and three children, and said he would make a decision with their input.

“I have always believed the sport of football is an ‘all-in’ proposition — if a 100% competitive commitment isn’t there, you won’t succeed, and success is what I love so much about our game,” Brady said in his Instagram post.

He added: “This is difficult for me to write, but here it goes: I am not going to make that competitive commitment anymore. I have loved my NFL career, and now it is time to focus my time and energy on other things that require my attention.”

After Brady’s announcement, tributes from across the N.F.L. flowed in. The Patriots, for whom he played his first 20 seasons, thanked and congratulated him on social media

As did their owner, Robert K. Kraft, who in a statement said that he has “the greatest respect” for Brady and “always will.”

“You didn’t have to be a Patriots fan to respect and appreciate his competitiveness, determination and will to win that fueled his success,” Kraft said.

Brady’s decision to announce his retirement on his own terms underlined the control that has governed his professional life and career.

His perfectionist streak, intensity and a microprocessor of a brain enabled a player chosen by the New England Patriots with the 199th overall pick in 2000 — the seventh quarterback selected that year — to retire with three league Most Valuable Player Awards and as the N.F.L.’s career leader in touchdown passes, passing yardage and victories.

Brady added to those marks this season, when he threw for the most yards of his career. Instead of hobbling around, beset by knee and shoulder injuries, Brady danced around the pocket and rushed for his most yards in a decade, shattering the stereotype of an older quarterback and redefining what feels possible for aging athletes.

Only six quarterbacks before Brady had even attempted one pass after turning 42, according to the Sports Reference database. Combined, those players — George Blanda, Steve DeBerg, Doug Flutie, Warren Moon, Earl Morrall and Vinny Testaverde — threw for 37 touchdown passes at 42 or older. Brady, in his first season with the Buccaneers, in 2020, threw 40.

So many other details of his career seem fanciful enough to sound apocryphal.

In 20 full seasons as a starter, Brady led his teams to 10 Super Bowls. He started as many Super Bowls (three) in his 40s as he did in his 20s, when he crammed three triumphs into four seasons. His seven Super Bowl titles are more than any single organization has won. He was selected as the Super Bowl M.V.P. five times; only one other quarterback, John Elway of Denver, even started five Super Bowls. Only once has Brady missed the playoffs as a starter — in 2002, the season after winning his first Super Bowl, the championship that began the Patriots’ dynasty.

Brady’s stardom in some ways sprung from a fluke event. He was just New England’s backup on Sept. 23, 2001, when the starting quarterback, Drew Bledsoe, was knocked out of the second game of the season with a sheared blood vessel in his chest.

Brady formed, with Bill Belichick, the greatest quarterback-coach partnership in N.F.L. history, capitalizing on the Patriots’ stable infrastructure, the league’s short-passing boom and his own durability — the only games he missed because of injury came in 2008, after he tore a knee ligament in the season opener. He reveled in New England’s “Do Your Job” ethos and emerged as a pocket passer extraordinaire, winning six championships and 17 division titles with the Patriots.

But even his playoff defeats were memorable. He was twice foiled in the Super Bowl by the New York Giants. The first time, in February 2008, thwarted New England’s bid for an unbeaten season. The second, in February 2012, prompted Bündchen, incensed by several dropped passes, to scoff afterward that her husband couldn’t throw and catch at the same time. Then, against the Philadelphia Eagles six years later, Brady torched the Eagles for 505 passing yards — one of his many postseason records — but lost, 41-33, after being stripped of the ball with about two minutes remaining.

Perhaps his crowning achievement came at the end of the 2016 season, when the Patriots overcame a 25-point third-quarter deficit to stun the Atlanta Falcons in the Super Bowl. For Brady, it was an act of redemption. He had started that season with a four-game suspension for his role in a cheating scandal known as Deflategate, a controversy about underinflated footballs meant to give him an advantage throwing the ball. The situation became a circus for the sport and at one point even reached federal court.

That championship, like so many other moments, reaffirmed Brady’s enduring belief in himself. Every team, including New England, bypassed him multiple times during the 2000 draft, and Brady was so distraught that no one had taken him in earlier rounds that he left his California home to take a walk before the draft had ended.

A few weeks after the Patriots selected him, Kraft encountered Brady not far from his office. Brady introduced himself to the team’s owner, who said he knew that Brady was their sixth-round pick from the University of Michigan.

“That’s right,” Brady replied, in Kraft’s retelling. “And I’m the best decision this organization has ever made.”

And he was, becoming one of the most beloved athletes in Boston sports history. But in August 2019, on the eve of his 20th year in New England and two days after turning 42, Brady agreed to a new contract that would make him a free agent after the season. His final pass as a Patriot, in a home wild-card round defeat to the Tennessee Titans, was intercepted and returned for a touchdown.

Two months later, with the Patriots unwilling to sign Brady to a long-term contract, he fled New England for the Tampa Bay Buccaneers in a move that upended the N.F.L. landscape. At the time, the Buccaneers had won as many playoff games (six) as Brady had championships, but he mastered a new offense, adjusted to new teammates and coaches and dominated the league, all while the pandemic restricted in-person contact. He won his seventh title, throwing three touchdown passes in a demolition of the Kansas City Chiefs last February in the Buccaneers’ home stadium.

Each of Brady’s Super Bowl championships proved something, in its own way. That he deserved to start. That he could spearhead a dynasty. That he didn’t need deflated balls to win. That the Patriots had made the right decision to retain him when he was over 40. And finally, last year, that he didn’t need Belichick to win.

Even in capturing his last two championships, when he had to outlast Kansas City quarterback Patrick Mahomes, Brady asserted his primacy and fended off the creeping generational shift at quarterback.

In recent years, Brady has been preparing for the next phase of his life, founding the wellness company TB12 Sports with his longtime trainer Alex Guerrero and the media company Religion of Sports and the Brady Brand clothing line. Sensing the end approaching, he also chronicled his legacy in two television series, “Tom vs. Time” and “Man in the Arena,”

But Brady kept delaying retirement because he loved football and he loved winning and he was excellent — the best, in fact — at doing both. That he finished his career with a playoff defeat, 10 days ago to the Rams, seems incompatible with all the glory that he had achieved,

Look again, though, at the piercing final play from that game: A 30-yard Rams field goal, the ball snapped from the Tampa Bay 12-yard line. A farewell to TB12, from the T.B. 12.