Dileo committed to play for the University of Michigan in April 2009 and enrolled in 2010. As a true freshman, Dileo appeared in seven games for the 2010 Michigan Wolverines football team. As a sophomore, he appeared in all 13 games for the 2011 Michigan Wolverines football team, including Michigan's victory in the 2012 Sugar Bowl. He scored his first touchdown for Michigan on a 19-yd pass from Denard Robinson with 1:05 left in the 3rd quarter to give Michigan a 28-3 lead which led to a 31-3 win against Eastern Michigan on September 17, 2011. On October 1, 2011, he caught a 17-yd touchdown pass thrown by running back Vincent Smith with 14:52 left in the 2nd quarter to give Michigan a 21-0 lead in a 58-0 victory over Minnesota. In Michigan's Sugar Bowl victory over Virginia Tech, Dileo threw a pass on a faked field goal that was tipped and caught by Michigan's long snapper for a first down at the Hokies' eight yard line. Dileo was also the holder on the game-winning field goal as time expired in the Sugar Bowl which led to a 23-20 win over Virginia Tech.
2012 season
As a junior for the 2012 Michigan Wolverines football team, Dileo appeared in all 13 games and caught 20 passes for 331 yards and two touchdowns. Playing against UMass on September 15, 2012, Dileo recorded a career-high 91 receiving yards, including a 66-yard reception in a 63-13 win. In a 12-10 victory over Michigan State on October 20, 2012, Dileo improved on his career high with 94 receiving yards. Clutch receptions by Dileo set up three field goals for Michigan against Michigan State. Michigan trailed 10-9 when Dileo's 20-yard reception with 18 seconds remaining set up the game-winning field goal. Dileo also scored on a 45-yard touchdown pass from Devin Gardner in Michigan's 35-13 victory over Minnesota on November 3, 2012. In the broadcast of the Michigan-Minnesota game, the television announcers from the Big Ten Network "compared Dileo to Wes Welker, the New England Patriots' hustle man." In addition to receiving duty, Dileo also returned punts and kickoffs for Michigan, and was the holder on extra points and placekicks. His versatility and work ethic have earned him the nickname, "Mr. Get It Done." Michigan's offensive coordinator Al Borges said of Dileo: "You need something done, send Drew. Whether it's holding for field goals, or needing an extra punt returner or running an option route, send Drew. He'll do it. Drew isn't going to make any errors. He's going to catch anything he can get to."
2013 season
As a senior during the 2013 season, Dileo continued to serve multiple roles as a wide receiver, kickoff return specialist, and holder on extra points and kickoffs. He had a 36-yard reception against Central Michigan on August 31, 2013, and scored Michigan's final touchdown with 4:18 remaining in Michigan's 41-30 victory over Notre Dame on September 7, 2013. Dileo finished the season with 16 receptions for 174 yards and two touchdowns.
