The 6-foot-3, 205-pound Hopper spent time looking at the campus and sitting with defensive coordinator Todd Grantham talking defense.
Hopper, who was also supposed to check out North Carolina and North Carolina State this week, said the visit went to well that Louisville "moved up," on his list.
"I would say they're in the top," Hopper said. "I really liked them and loved talking to coach Grantham, so they're in my top list of schools."
Hopper has 20 scholarship offers and has visited Tennessee several times, while camping recently also at Mississippi State. He said he has family in North Carolina.
He said Grantham told him he would "be a great fit" for Louisville's outside linebacker spot. He is hoping to make a return trip soon to the Cardinals.
"I liked the campus and the dorm rooms are really nice," Hopper said. "It just seemed like a great place and I really liked coach Grantham a lot."
Hopper said he doesn't have a timetable for a decision.