Hill, No. 7 in the 2023 ESPN 300, chose the Aggies over Texas.
The 6-foot-2, 230-pound Hill, from Billy Ryan High School in Denton, Texas, recorded 131 tackles (93 solo) with 18 tackles for loss and eight sacks as a junior in 2021.
With coach Steve Sarkisian and Texas stealing a lot of the recruiting limelight in the state recently, Hill gives Fisher the key recruit the Aggies' 2023 class had been lacking.
Also on Saturday, the Aggies added another highly ranked defensive player when Dalton Brooks, a 6-1, 175-pound safety from Shiner, Texas, announced his commitment on Twitter.
Hill and Brooks are the fourth and fifth ESPN 300 prospects for Texas A&M in this cycle and the latest to commit within the past week after offensive lineman Chase Bisontis announced July 24.
"I feel like I'd be good at that -- just trying to get guys to play with [me]," Hill told ESPN last month. "Whatever squad I go to, I want to win a national championship and I just want to be a great teammate, great leader. So whatever school I go to, I initially want to be around some of the top guys."
ESPN currently has Texas A&M's class unranked.
ESPN's David Wilson contributed to this report.