Murray, who picked A&M over Oregon and Auburn, chose to follow in the footsteps of his father, Kevin, who was a two-time All-American with the Aggies.
Despite the family connection, the Ducks and Tigers made late pushes before Murray made his final decision Tuesday night.
The win for A&M is another sign that the Aggies have capitalized on the popularity of 2012 Heisman Trophy winner Johnny Manziel, the production of multiple first-round NFL draft picks and the move to the Southeastern Conference to surpass rival Texas for in-state talent.
The Aggies now have commitments from two of the state's top three prospects in Murray and defensive tackle Daylon Mack (No. 15 recruit). They also are squarely in the mix for the top-ranked prospect in Texas, No. 12-rated Kendall Sheffield, who is a cornerback.
The state's top-ranked prospect in 2014 (No. 4 overall), defensive end Myles Garrett, also signed with Texas A&M.
The Aggies have ascended every year in the recruiting rankings under coach Kevin Sumlin, going from No. 15 in 2012 to No. 8 in 2014 and No. 4 this past year.
With Murray's pledge, the Aggies move up to No. 2 behind Alabama in the ESPN class rankings for 2015 with a group that is currently headlined by eight ESPN 300 prospects.