Jones' departure comes two days after quarterback Sam Darnold said he would join the professional ranks.
Jones, 20, leaves USC fifth on the school's career rushing list with 3,619 yards in 591 carries, a 6.1-yard average. He had 14 100-yard games and scored at least one touchdown in 19 of his final 20 games.
"After much thought and prayer, I have decided to forgo my final year of eligibility to pursue my lifelong dream of playing in the NFL," Jones said in a statement in which he went on to thank family, friends and the USC coaching staff.
During the run-up to the Cotton Bowl, Darnold and others said they had not made a decision on the draft, preferring to wait until after the game. However, Jones said he went into the game knowing it would be his last as a Trojan.
"I guess the decision was made around Christmas," he said. "My family and I thought that I put together a pretty good year. And obviously running backs have a pretty short life span at the next level."
He said he spoke with USC coach Clay Helton after last week's bowl game and Helton told him he supported his decision either way.
Jones, a first-team All-Pac-12 Conference choice, rushed for 1,550 yards this season, the eighth-best total in Division I. His 19 rushing touchdowns were tied for fifth best.
The 6-foot, 200-pound speedster, who ran 100 meters in 10.37 seconds as a Texas high schooler, has been projected as a likely second-round selection, a projection he hopes to raise during tryouts for NFL scouts.
"I would love to go in that round," he said. "With the workouts and the support that I've always had — and the continued support that I'm going to have moving forward — I think I can be able to [move up].
"It's a lifelong dream and goal that I have to go and accomplish. I've never been through this obviously. I'm still trying to figure it out as the day goes by."
Jones said he has been getting advice from coaches and former college players who have been through the process. He also said he is six classes shy of a degree in communications and intends to complete his work.
"I'm promised my mother I would finish school," he said. "So that's on your bucket list."
Jones' departure leaves USC thin at tailback. Stephen Carr is the leading returning rusher, having run for 363 yards on 65 carries as a freshman. Redshirt freshman Vavae Malepai and junior Aca'cedric Ware were the only other players who had more than seven carries.
Jones is unlikely to be the last USC player to give up his final season of eligibility. Wide receiver Deontay Burnett, linebacker Cameron Smith, defensive lineman Rasheem Green and second team all-conference tackle Toa Lobendahn are all reportedly considering turning pro as well.
Players have until Jan. 15 to declare for the draft.
Follow Kevin Baxter on Twitter @kbaxter11
12:15 p.m.: This article was updated throughout with additional details and background.