Richardson attended Cisco College in 2008, a local Texas community college where he rushed for 526 yards and 7 touchdowns on 95 attempts.
Richardson then transferred to Abilene Christian, which he attended from 2009 to 2011. Appearing in 34 games with 23 starts for the Wildcats, Richardson amassed 2,303 yards on 453 carries with 34 touchdowns.
Richardson was selected in the seventh round (252th overall) of the 2012 NFL Draft. He was picked second to last in the draft, the only player behind him was Northern Illinois quarterback Chandler Harnish, who was selected by the Indianapolis Colts with the 253rd pick.
On June 6, 2012, Richardson signed a four-year contract with the Rams worth $2.15 million. During his rookie campaign, he was the primary backup to then Rams starting running back Steven Jackson over fellow draftee, second-round pick Isaiah Pead. Richardson played in all 16 games, gaining 475 rushing yards on 98 attempts, as well as 24 receptions for 163 yards. His best performance came in Week 2 of the regular season against the Washington Redskins when he rushed 15 times for 83 yards and scored a 2-point conversion.
Richardson was waived by the Rams on May 15, 2014.
Richardson was claimed off waivers by the New York Jets on May 16, 2014. He was released on August 30, 2014, but signed to the team's practice squad a day later. Richardson was signed a to reserve/future contract on December 30, 2014. The Jets released Richardson as part of their final roster cuts following the 2015 preseason.
The Houston Texans signed Richardson to their practice squad on September 23, 2015 before releasing him on October 20. The Houston Texans signed Richardson to their practice squad again on October 28, 2015.
Richardson signed with the Cleveland Browns on December 15, 2015. Richardson was inactive for 2 games after being signed. The Cleveland Browns waived Richardson on December 28, 2015.
On January 20, 2016, the Pittsburgh Steelers signed Richardson to a future/reserve contract. He was released by the Steelers on September 29, 2016 and was signed to the Steelers' practice squad on October 3. He was promoted to the active roster on November 19, 2016. He was released on December 24, 2016.
Richardson was claimed off waivers by the Jaguars on December 26, 2016. On May 1, 2017, he was released by the Jaguars.
On August 29, 2017, Richardson signed with the Indianapolis Colts. He was released on September 2, 2017.
Richardson is the brother of running back Bernard Scott, and cousin of wide receiver Clyde Gates. Richardson married Morgan Myrick, his college sweetheart, at Abilene Christian University on March 21, 2015.