After redshirting for the 2008 season, Cox saw limited action on the Wolverines roster from 2009 to 2011. Cox would play in 15 games over three years, rushing for 169 yards and two touchdowns. Cox' best single game for the Wolverines was during his redshirt freshman season, against Delaware State when he rushed for 82 yards and two touchdowns. Cox graduated from Michigan in the spring of 2012. With one year of eligibility remaining Cox transferred to UMass. Due to NCAA regulations, since Cox already obtained his undergraduate degree, he was not required to sit out one season under normal transfer guidelines. Cox would serve as the feature back for the Minutemen. He started all 12 games, and despite running behind an inexperienced offensive line, Cox rushed for 715 yards and five touchdowns, leading the team in both categories. Against Miami Cox recorded the best game of his career with 188 yards rushing on 30 carries and two touchdowns. Cox would also register 81 yards against his former team Michigan.
Cox was drafted by the New York Giants with the 253rd pick, in the seventh round of the 2013 NFL Draft. Cox made his first professional start on Monday Night Football on October 21, 2013. He was waived on April 27, 2015.
Personal
In November 2013, a New York Times report revealed events that not only the Giants organization was unaware of about Cox, but that Cox himself had not fully become aware of until he was 13 years old. The report detailed how Cox's father, Michael A. Cox Sr., a Boston police officer, had been the victim of a mistaken but vicious beating by fellow police officers in 1995. The beating of Michael Cox investigation was all but tossed under the rug, and became infamous as "Boston's Rodney King case." Eventually, Cox's father sued and was awarded $900,000 by the Boston police department, which he continued to serve as a superintendent until 2019. In 2020, the older Cox became the Chief of police in Ann Arbor, Michigan. Cox's mother, Kimberly, is an anesthesiologist, and he is the eldest of her and Michael Cox Sr.'s three children. Michael's younger brotherNicholas Cox is a former football player at a division 1 AA program University Of Maine and briefly tried out for the Baltimore Ravens after going undrafted in 2014.