The Southern California senior was nearly flawless after halftime Wednesday night, completing 16-of-19 passes for 218 yards and a touchdown. But Young scored on an 8-yard run with 19 seconds remaining to give No. 2 Texas the national championship with a 41-38 victory over the top-ranked Trojans in the Rose Bowl.
"We just couldn't tackle him," Leinart said. "I still think we're a better football team. They just made the plays at the end.
"This is what it's all about, 41-38 in the final game," he added. "You couldn't ask for anything better. This was a great football game. We gave our hearts, they gave their hearts, and they came out on top."
Leinart threw an incompletion to finish his career, overthrowing Dwayne Jarrett as time ran out, and trudged off the field a loser for only the second time in 39 starts at USC.
The 2004 Heisman Trophy winner didn't seem himself during a shaky first half, perhaps feeling the rust of a month off. The Trojans moved inside the Texas 20-yard line four times in the first half and to the Longhorns' 25 on another occasion but scored only 10 points.
"It's disappointing. We missed some stuff in the first half, but that's the way things go," Leinart said.
He was sacked twice in a row in the final minute of the half to prevent USC from perhaps scoring a touchdown. He knelt on one knee after one of the takedowns with his helmet off, appearing shaken up and in need of the halftime break.
Once he got it, there was no stopping him or his team for a while as USC (12-1) scored touchdowns on its first four possessions of the second half to take a 38-26 lead.
But Texas (13-0) had what it took at the finish.
Next stop for Leinart: The NFL, where he could have played this season, assuring himself of all the money he could ever spend.
That'll come soon enough for the 6-foot-5 left-hander from Orange County, who decided to go with his heart and stay in school for his senior year.
"No regrets," he said. "This is what I came back to school to do."
Leinart beat out three competitors to win the starting quarterback job in the spring of 2003 after sitting out his first year and playing third string his second, playing in mop-up time in three games without throwing a pass.
He has excelled in his three years as a starter to the point where it's reasonable to call him one of the best quarterbacks in college football history.
"He's got to be one of the all-timers, he's got to be," USC coach Pete Carroll said. "He's one of the top few that's ever played."
If that's not the case, Leinart certainly qualifies as one of the most successful with his 37-2 record as a starter -- including a 34-game winning streak snapped by the Longhorns.
"He's been a great champion, he's been a great leader, he's been a role model, he's been a blast to be around," Carroll said. "You know it and I know it, it's time to go.
"He played fantastic tonight again; it's just too bad he couldn't walk out of here as the Rose Bowl champ one more time. It isn't because he didn't do all he could," Carroll said.
Among the other outstanding records by starting college quarterbacks are the 35-0 mark by Toledo's Chuck Ealey from 1969-71, the 32-1-1 record by Oklahoma's Steve Davis from 1973-75 and the 38-2 mark by Miami's Ken Dorsey from 1999-2002.
Young is 30-2 as a starter and could surpass Leinart's standard as a senior next season, assuming he returns to school.
Carroll said Leinart's decision to play his senior year was the right one and should send a message to other youngsters.
"He's such an extraordinary kid," Carroll said. "I know he wouldn't trade this experience for anything. We're very lucky that we've had the time with him; it's been great to be with Matty."
Leinart went 29-of-40 for 365 yards with one interception against Texas. He was at his best in USC's most important games, winning MVP honors in the Rose Bowl two years ago, when he completed 23-of-34 passes for 327 yards and three touchdowns in a 28-14 victory over Michigan, and in the Orange Bowl last January, when he hit on 18-of-35 for 332 yards and five TDs in a 55-19 triumph over Oklahoma.
Leinart passed for a startling 10,603 yards and 99 touchdowns with only 23 interceptions in the past three seasons.