The 6-foot-9, 230-pound Thomas chose the Aggies over finalists Oklahoma State, Illinois, SMU and LSU. He took trips to all five schools over the past six weeks, but A&M received the final visit and won him over.
"They were the first school to offer me a scholarship," Thomas told ESPN.com. "On my official visit, when I saw their academic system, I loved it. And third, I felt the system, relationship with the committed players, coaches -- especially head coach Billy Kennedy -- and the current players.
"They're a huge family, and I want to be a part of something special. I feel like we can win a national championship my freshman year. That was the deciding factor."
Thomas kept people guessing throughout his recruitment, with each of his finalists seemingly having an edge at some point down the stretch. Oklahoma State and Illinois were the major factors coming out of the summer, while LSU received his first visit -- and also offered him the chance to play football -- and SMU made a late push.
Last week, though, ESPN 100 guard Admon Gilder committed to Texas A&M. Thomas and Gilder have been friends since second grade, and that likely had an impact on his decision.
"That's just a perk," Thomas said. "That's my brother, and he didn't change my mind; he just made things easier."
Thomas joins a Texas A&M recruiting class that also includes post player Tyler Davis (No. 20 in ESPN 100), small forward D.J. Hogg (No. 35) and Gilder (No. 64). Prior to Thomas committing, it was a group ranked No. 5 in the country for the Class of 2015. With Thomas in the fold, it cements A&M's class among the elite.
Although Kennedy and the Aggies have had some ups and downs, Thomas' commitment and the 2015 class in general have them positioned for a big rise over the next few years.
"I feel I will fit in perfectly. We plan on winning the 2016 national championship," Thomas said. "We're going to change things by winning, making it an all-around school instead of a football school. A&M is not only on the rise, we are tiptoeing to the top."