Carton took a leave of absence from the Buckeyes in late January, citing mental health as the reason.
"Buckeye Nation, I first want to say thank you to all the Ohio State fans who supported me during the difficult times I went through this year," Carton wrote on Twitter. "I also want to thank the university, my teammates, the coaches and all the staff who went above and beyond to help my family and me this year. After some careful thought and consideration, I have decided to make a fresh start and enter the transfer portal. I wish Coach [Chris] Holtmann and my teammates the best of luck next year. Please respect my decision."
Ohio State released a statement shortly before Carton's announcement.
"We 100% support D.J. in this decision and we genuinely wish him all the best moving forward," it said. "We appreciate all he contributed to our program. We will assist him in any way we can."
Carton, a 6-foot-2 guard, played a key role for Ohio State before taking his leave of absence, starting three games and playing at least 18 minutes in all 20 games. He averaged 10.4 points and 3.0 assists, ending his Ohio State career with 17 points and three assists in a win over Northwestern. He was a former ESPN 100 recruit who chose the Buckeyes over Indiana and Michigan.