The Trojans' staff already had its chance to observe Austin at their O-Line/D-Line camp in early June.
"I had a big time performance at that camp," Austin told FOX Sports NEXT on the telephone.
It was a big enough performance, he found out Wednesday, to earn himself a scholarship offer from the Trojans.
"I'm starstruck...speechless...ecstatic," Austin said. "I'm on a high, on my way home now."
The Scout.com three-star prospect says he thought there was a possibility he could pick up an offer since his performance at USC earlier this month, but was nevertheless surprised.
Austin, 6-foot-5 280-pounds, said offensive line assistant James Cregg has been in charge of his recruitment. He's also spent time talking with offensive line coach Mike Summers.
"The coaches," he said, "I love how they coach, they're professional. They will push me to the limits."
A 4.3 student in the classroom, Austin says USC's academic and athletic tradition look like a perfect match for him. "I'm really starting to fall in love," he said. "Their academics, you graduate from there with a key to the city and lots of connections.
"The coaches, the facilities - they're the best. They blew me away and there is such a sense of camaraderie," he continued.
Austin is a candidate to enroll early, he says he's on track to be a mid-year graduate. He explained that he couldn't linger at USC Wednesday after Rising Stars, having to get home for high school practice and summer school.
Austin said the only thing keeping him from potentially committing to USC on the spot was the fact his mom wasn't with him on campus today. "I will probably call later tonight or tomorrow," he said.
Keep it on FOX Sports NEXT for the latest on Jordan Austin.