James at last seized control of his own narrative Thursday night, leaving nothing to chance and no more room for debate. He drove hard, shot brilliantly, scored every critical basket and finally pushed the Miami Heat past the San Antonio Spurs for a 95-88 victory in Game 7 of the N.B.A. finals.

As red and white confetti rained from the rafters at American Airlines Arena, James — oft vilified, perpetually scrutinized — soaked in the revelry and embraced a new identity: back-to-back champion.

There were still doubters out there, somewhere, beyond the clouds of fluttering paper, but their ranks are surely shrinking.

“I can’t worry about what everybody says about me,” a joyful James said on the championship podium after receiving his second straight finals Most Valuable Player trophy. “I’m LeBron James, from Akron, Ohio, from the inner city. I’m not even supposed to be here.”

James came here three summers ago in pursuit of championship glory, to join Dwyane Wade and Chris Bosh in a superstar lineup for the ages, to start collecting championships — “Not one, not two, not three … ” he infamously declared in July 2010. The banners are indeed starting to accumulate, with James earning this second title despite diminishing returns from his co-stars.

With Wade slowed by an injured right knee, James carried a greater burden this June than he did a year ago. And he faced a tougher, more seasoned opponent, a decorated Spurs team with three Hall of Fame talents in Tim Duncan, Tony Parker and Manu Ginobili.

It took seven games, including a furious comeback and an overtime in Game 6, to earn this moment. And then it took everything James had in the final minutes of the final game.

“The toughest series we’ve ever been in,” Heat Coach Erik Spoelstra said.

After leading the Heat’s comeback two nights earlier, James carried them to the finish with a 37-point, 12-rebound outburst on Thursday. He had 8 points in the final 5 minutes 39 seconds, repelling every attempt by the Spurs to take the game back.

The lead dropped to 2 points just once, on Kawhi Leonard’s 3-pointer with two minutes to go. James answered with an 18-footer, then a pair of free throws. The building rumbled in anticipation and then finally exploded, the Heat celebrating their third title since 2006.

Wade pushed through the knee pain and limitations, delivering 23 points, 10 rebounds and 2 blocks. Afterward, he insisted on being called “Three,” in reference to his third championship.

“They played Hall of Fame basketball tonight,” Spurs Coach Gregg Popovich said of James and Wade. “That’s some of the best basketball they both played at the same time throughout the entire playoffs, from what I saw.”

The Heat, despite a scoreless game from Bosh, joined the Los Angeles Lakers as the only teams with back-to-back titles in the post-Michael Jordan era. They did it by becoming only the fourth team to win Games 6 and 7 at home after facing a 3-2 deficit. It was the first time in this series that either team won two in a row.

It was a heartbreaking conclusion for the Spurs, who came within seconds of winning the championship in Game 6. Duncan was aiming for his fifth title, which would have placed him alongside Kobe Bryant for the most by any star in the post-Jordan era. This was his first defeat in the finals, and it hit hard.

Sitting on the postgame podium, Duncan looked inconsolable. He stared down at the table, his left hand on his head, and paused frequently between phrases. He bemoaned his “bad decisions” and missed shots, in particular two point-blank shots that could have tied the game at 90-90 with about a minute to play.

Still, Duncan was mostly brilliant, finishing with 24 points, 12 rebounds and 4 steals. Ginobili added 18 points and 5 assists but had four turnovers, all in the fourth quarter.