It was PSU's first win at Michigan since 1996.
Clark completed 16-of-27 passes for 230 yards, and his four touchdowns equaled a single-game career high.
Running back Evan Royster gained 100 yards on 20 carries, and linebacker Navorro Bowman made 11 tackles, an interception, a sack and a fumble recovery for the Nittany Lions (7-1, 3-1 Big Ten), who have won four in a row since a 21-10 home loss to Iowa on Sept. 26.
Freshman quarterback Tate Forcier led Michigan's inept offense with 13-of-30 passing for 140 yards with an interception, one of the team's four turnovers.
Brandon Minor scored once, but was held to 48 yards on 12 carries, and Jason Olesnavage kicked a 23-yard second-quarter field goal for the Wolverines (5-3, 1-3), who have lost three of four.