Allen scored the most points by a champion in the state's highest classification in front of the biggest title game crowd in Texas history - 54,347 at the $1.2 billion home of the Dallas Cowboys.
The No. 1 team in the final Associated Press poll won its 27th straight game a week after a semifinal victory against DeSoto, the second-ranked team at the end of the regular season.
It was the third state title in three trips to the championship game for Allen (16-0), all in the past six years.
Connor Heath was 16 of 31 for 110 yards with two touchdowns and two interceptions for Pearland (14-2).
Allen became the first team to score 60 points in a title game in the highest classification. Lewisville Marcus had the previous high in a 59-20 victory against Alief Hastings in 1997.
Pearland couldn't pull another upset three years after knocking off top-ranked and defending champion Euless Trinity in the school's first championship game appearance.
Murray, a junior in his second season as Allen's starting quarterback, passed for 280 yards and had a 37-yard scoring run for his team's final points with 7:14 remaining.
Pearland scored a touchdown on its opening drive and led again 14-7 after Zachary Boegler's 1-yard touchdown run in the first quarter.
That lead lasted 19 seconds - the length of time it took Chad Adams to score on a weaving kickoff return.
After spinning off a tackler, Adams ran to the middle of the field and then back to the right sideline. A Pearland defender hit Adams but he reached the ball out to the pylon for the game-tying touchdown.
Murray led three touchdown drives in the second quarter and three more in the third. Murray wasn't sacked while completing 11 of 14 passes with one interception as Allen racked up 670 yards on offense.
Allen took the lead for good in the first minute of the second quarter on Murray's first touchdown pass, a 19-yarder to Jalen Guyton.
Guyton and Cole Carter each caught two scoring passes for Allen. Jaelen Barlow ran for two touchdowns. Adams had a touchdown rushing to go with his kickoff return.
Barlow gained 134 yards rushing on 18 carries. Guyton caught four passes for 125 yards, and Carter had five receptions for 111 yards.
None of Allen's seven touchdown drives lasted more than six plays, but Allen had four turnovers, three of which led to touchdowns for Pearland.
Four different players scored for Pearland. The leading rusher was Hayden Cole with 88 yards on 18 carries.