Miller decided to play for University of Miami rather than University of Florida (near his mother's hometown) to stay close to home, and to follow the footsteps of other former Hurricanes running backs. After he was redshirted in 2009, Miller saw his first game action in 2010. He played in 11 games with one start and rushed for 646 yards on 108 carries with six touchdowns. Miller took over as the Hurricanes starting running back in 2011. During the 2011 season, Miller became the first Miami running back since Willis McGahee in 2002 to rush for over 1,000 yards in a season.
Miller was drafted by the Miami Dolphins in the 4th round of the 2012 NFL Draft, 97th overall on April 28, 2012. He was the second Miami Hurricane selected by the Dolphins in that year (the other was defensive end Olivier Vernon.) They were the first Hurricanes drafted by Miami since Vernon Carey in 2004. The last pair of UM prospects to be selected by the Dolphins in the same Draft had been in 1991 when Randal Hill and Roland Smith trailed the same path. On June 1, 2012, Miller signed a 4-year, $2.58 million contract, including a $480,000 signing bonus.
Miller scored his first career touchdown, a 15-yard run, in a Week 2 match-up against the Oakland Raiders on Sept. 16, 2012. During the 2014-2015 NFL Season he was the starting running back for the Miami Dolphins, eclipsing 1,000 yards in the final game of the season.
In 2014, Miller rushed for 1,099 yards and 8 touchdowns averaging 5.1 yards per rush. In the last game of the season he scored a 97-yard touchdown against the New York Jets and set the franchise record for longest run.