Robinson matched his season-high by throwing for 338 yards and ran for 113 as Michigan (6-0, 2-0) scored on its first three possessions of the second half. The Wolverines trailed 24-14 after a first half in which Robinson threw three interceptions.
Michigan's Junior Hemingway caught five passes for 123 yards and Roy Roundtree added five grabs for 83 yards.
Michigan has won nine of the last 11 meetings between the schools, though they hadn't met since Northwestern's win at Michigan Stadium in 2008.
With Michigan trailing by 10 points, Robinson came out firing in the second half. He connected with Roundtree on a 57-yard bomb to set up Robinson's two-yard touchdown scamper. After a stop, Robinson led an 80-yard drive, accounting for 68 yards himself, and Devin Gardner scored on a one-yard run to put Michigan up 28-24.
Michigan's Brandin Hawthorne then picked off Persa's tipped pass, setting up Michael Shaw's three-yard touchdown run. Northwestern had the ball for just 2 minutes, 32 seconds during the third quarter.
Ebert fumbled after a short reception from Persa, giving Northwestern two straight turnovers after turning the ball over just two times total in their first four games. After shutting out Northwestern in the second half, Michigan has allowed just 21 second-half points in six games and has forced nine second-half turnovers.
After winning their first five games at home, the Wolverines were playing their first road game of the season, though the Northwestern purple in the crowd at Ryan Field had a liberal sprinkling of Michigan maize that gave the game a Big House-like feel.
The Wolverines started fast. Robinson hit Junior Hemingway on a key third-down pass for 48 yards. The senior outleapt safety Ibraheim Campbell to make a tumbling catch, and Denard found Steve Watson from nine yards out for the game's first score.
Persa led three long Northwestern scoring drives in the first half. Northwestern's 14 first-quarter points were more than Michigan allowed in its three previous games combined. The Wolverines entered the game allowing just 10.2 points per game, second in the nation and down from 35.2 last season.
Meanwhile, Robinson's erratic throws kept Michigan off the scoreboard. Robinson entered the game with a Big Ten-high six interceptions and he threw three more - all on overthrows - in the first half.
Campbell had two of the interceptions, his second coming on the first play of the second quarter after Michigan reached Northwestern's 16-yard line. It was the second time all season that Michigan didn't score inside the 20 - the first was a kneel-down to end last week's 58-0 win over Minnesota.
But after halftime, it was all Robinson and Michigan, which converted 14 for 17 on third-down conversions in the game.