The UNC coaching staff had evaluated Riley, a 6-foot, 205-pound tailback from Kannapolis Brown, on film before Saturday's junior day. However, they were waiting to receive his transcripts before deciding to offer.
"I was happy when they offered," Riley said. "I've been waiting for a while, so it's good to finally get one."
Besides UNC, Riley is fielding significant interest from Duke, Georgia Tech, and Wake Forest.
With the offer, UNC has become Riley's leader.
"Right now, I do like Carolina probably the best," Riley said. "But I need to look at some more schools and see what's out there."
Riley is in the process of planning a trip to Wake Forest to see a spring practice. He also plans to camp at Georgia Tech, Illinois, UNC, and Wake Forest this summer.
Saturday's Junior Day marked Riley's first recruiting visit to UNC. He had previously attended a game there as a fan.
The activities surrounded UNC's Saturday afternoon spring practice.
"I enjoyed the way Coach [Butch] Davis runs practice," Riley said. "It's up-tempo and very organized."
Riley also received a tour of Kenan Football Center.
"I feel like facility-wise, it's top notch," Riley said. "They're about to add to the stadium. I like what they got up there and what they're getting ready to do."