Robertson attended Lamar High School in Houston, Texas.[2] Robertson was selected to the first team All-District 20-5A honors.[2] Robertson finished high school with 83 tackles, 11 sacks along with 2 fumble recoveries.[2] Robertson was named one of state's Top 25 defensive linemen by Texas Football magazine.[2]
In his freshman year, he played 9 games coming off bench.[2] On October 4, 2008, he recorded a season high 2 Tackles against the No.1 ranked Oklahoma but Baylor lost in a blowout 49-17.[3] On November 1, 2008, he had just one tackle against Missouri but Baylor lost 31-28.[4]
In his sophomore year, he played in all 12 games, and started at defensive end.[2] He finished the season with 22 tackles, including 5 tackles for loss, 3 sacks.[2] On October 17, 2009, he recorded a career high 5 tackles against Iowa State but Baylor lost 10-24.[5] On November 7, 2009, he recorded 5 tackles and 2 sacks against Missouri and Baylor won 40-32.[6] On November 28, 2009, in the season finale against Texas Tech, he recorded 2 tackles and one sack but Baylor lost 20-13.[7] Baylor finished the 2009 season with a 4-8 record.
In his junior year, he played 10 games and started 9 of them.[2] He started the season as a defensive tackle until the fourth game.[2] He missed the next three games due to injury.[2] On September 11, 2010, he recorded 3 tackles, including two tackles, and three QB hurries against Buffalo in which Baylor won 34-6.[8] On October 16, 2010, he just recorded 2 tackles against Colorado and Baylor won 31-25.[9] On October 23, 2010, he recorded 4 tackles Kansas State contributing to Baylor winning the game by the final score of 47-42.[10]
In his senior year, he played in 13 games and started 11 games and he recorded 23 tackles and 4.5 sacks.[11] On October 1, 2011, he recorded 4 tackles and 2 sacks against Kansas State but Baylor lost 36-35.[12] In next game against Iowa State, he recorded one sack while Baylor won 49-26.[13]
On August 2, 2012, he signed with the Detroit Lions.[17][18] On August 31, 2012, he was released on the final day of roster cuts.[19]
New England Patriots
On January 1, 2013, Robertson was signed to the New England Patriots practice squad.[20] On April 29, 2013, the Patriots released Robertson.
Miami Dolphins
On June 13, 2013, he signed with the Miami Dolphins.[21] On August 31, 2013, he was released by the Dolphins.
Chicago Bears
On October 14, 2013, he was signed to the Chicago Bears practice squad.[22] On November 22, he was promoted to the active roster,[23] making his debut in week twelve against the St. Louis Rams, but was released on November 29.[24] He returned to the practice squad on December 3.[25] On August 30, 2014, he was part of the final cuts by the Bears.
Toronto Argonauts
On February 5, 2014, it was announced that Robertson had signed with the Toronto Argonauts.[26]