Gray finished the season with 59 rushing TDs, breaking the state record of 57 set by Sugar Land's Kenneth Hall in 1953.
Aledo (16-0) won its third state title in its fourth championship appearance. La Marque (11-4) is now 5-5 in 10 trips to the title game.
La Marque's Tim Wright had several spectacular runs but couldn't keep up with the steadiness of Gray, a junior. Wright finished with 198 yards and two touchdowns rushing.
Gray put Aledo ahead for good at 34-27 on a 42-yard scoring run with 1:28 left in the first half.
The go-ahead score was Gray's fourth touchdown of the first half, and he scored again from 9 yards on Aledo's second play of the second half.
Gray broke Hall's touchdown record with a 13-yard run that put Aledo ahead 55-34 early in the fourth quarter. He punctuated his night with a 54-yard scoring run, holding his right index finger in the air as he crossed the goal line for the eighth time on his 29th and final carry.
Barring injury, Gray will break the career touchdown record in Texas. It was set at 146 last year by Cayuga's Traylon Shead. Gray has 135.
Breaking Hall's hallowed state rushing record of 11,232 career yards will be tough, though. Gray has 6,965 career yards and would have to average 267 yards per game in another 16-game season to catch Hall.
La Marque kept pace into the third quarter, when quarterback Emanuell Williams scored on a 4-yard run to pull his team within 41-34.
La Marque had a chance to tie after a rare Aledo punt, but fumbled at its 40, one of five turnovers. Four straight runs by Gray followed, the last a 16-yarder that put Aledo ahead 47-34.
Williams passed for 246 yards and two touchdowns, but had three interceptions.