After reading a prepared statement during a news conference in the Heritage Hall lounge, Miner broke into tears when asked whether it had been a difficult decision.
"I think that answers the question," said Miner's aunt, Sharon Holland.
After regaining his composure, Miner said he had vacillated.
"I went back and forth, but in the back of my mind I always knew what I really wanted to do," he said. "I had a very close relationship with my teammates and the coaching staff, but I just looked at it as a situation where I'd just be moving on. I'll always be a part of USC.
"Long before my arrival at USC, I had the dream of playing in the NBA. That opportunity is presenting itself at this time. I think everyone would have to agree that it's hard to put one's lifetime dreams on hold when they are at the point of becoming reality."
Miner also cried as he spoke about how much he would miss his teammates.
Coach George Raveling was also overcome with emotion.
"That's the most emotional I've seen Harold in all the time he's been here," Raveling said. "The only other time I saw him cry was in the locker room after we beat UCLA at home.
"I think it's been a most difficult situation for all of us. We tried to make sure we got the necessary information to allow the Miner family to make a comfortable decision.
"I think I was torn down the middle. As someone who loves him and would like to think I'm his best friend, I'm happy for him."
Miner is a 6-foot-5 All-American guard who averaged 26.3 points last season and was named Sports Illustrated's college basketball player of the year. He said NBA scouts have told him he probably will be among the top six players chosen in the draft.
Miner said he plans to return to USC to get his degree and will donate $60,000 to USC to repay the cost of his scholarship.
Teammate Rodney Chatman said he wasn't surprised by Miner's decision.
"I wasn't as shocked as I thought I'd be," Chatman said. "Harold had some great years at USC."
Miner helped rebuild USC's basketball program, which had a 26-42 record in the three seasons before his arrival in 1989. The Trojans were 55-32 during Miner's three seasons, earning NCAA tournament bids the last two seasons.
Raveling predicted that the Trojans will be competitive next season, despite the loss of Miner, the leading scorer in school history. USC also loses two other starters to graduation, guard Duane Cooper and center Yamen Sanders.
"The natural tendency is to think we're not going to be any good," Raveling said. "But I still think we'll have a better basketball team than people think we're going to have. The reality of it is that we just faced the loss of Harold 12 months earlier than we had anticipated.
"I think we can still be a good team, we'll just be a different type of team. In the past, we always had Harold to bail us out."