During his freshman season, Benn caught 43 passes for 521 yards, both team highs and school freshman records, and scored two touchdowns. Benn also added 158 yards on 32 carries, along with returning 10 kickoffs for 280 yards, including a 90-yard return for touchdown against Penn State. He was named the 2007 Big Ten Freshman of the Year. During his sophomore campaign, Benn's stats improved to 67 rec and 1055 yards, 3 touchdowns (led Big Ten in receiving yards), and also contributed to the run game by rushing for 101 on 23 carries for 2 touchdowns. On August 10, 2009 Benn was named to the Walter Camp "Players to Watch" list for its prestigious Player of the Year award, the nation's fourth-oldest individual college football accolade. On August 12, 2009 Benn was named to 2009 Biletnikoff Trophy Watch list.
On March 15, 2013, Benn was traded to the Philadelphia Eagles, along with a 7th-round pick, for a 2013 6th-round pick and a 2014 conditional pick. On March 21, 2013, Arrelious Benn signed a one-year contract extension through 2014. On August 6, 2013, Benn tore his ACL. On August 7, 2013, Benn was placed on the Injured Reserve list, which officially ended his 2013 season. He was released by the Eagles on May 16, 2014. Benn was then re-signed by Philadelphia on May 19. Benn was placed on injured reserve on August 30, 2014. He was waived with an injury settlement on September 6.