Thornton committed to ISU last weekend in a post on his twitter account.
Thornton was getting looks from several schools, but Indiana State is the only school that tripped him and offered the opportunity to come in and play right away.
As a redshirt sophomore this past season, Thornton Jr. played mostly inside, but he did move outside at times as well, finishing with 33 tackles and 2.5 tackles-for-loss in nine games.
"I was mainly inside, but I transitioned outside on different occasions," Thornton Jr. told JCFootball.com back at the beginning of January. "The best part of my game is my coverage. I have good speed and I'm able to cover a lot of ground and my instincts are good too. I work really well in open space."
This offseason, Thornton has already gotten to work in the weight room to improve his strength and he's studying a lot of film on different defenses.
"I want to add size to my body to be able to really mix it up with those big guys up front," Thornton Jr. said. "I also want to work on my hips and be able to move around the field smoother and transition better."
Thornton will finish up his two-year degree in May and he will have two years to play two starting this fall.
Chad Thornton Jr. Scout Profile