Harrison was born in New Iberia, Louisiana on November 29, 1988. He attended Lake Charles Boston High School, where he primarily played shooting guard on the school's basketball varsity team. On November 29, 2005, during his junior season, he injured the meniscus in his left knee, and gained "like 40 or 50 pounds" over the next two months. He decided to take on football for his senior year, playing both offensive and defensive line, and was an all-district and all-Southwest Louisiana selection in 2006. He was also named as the team captain and was selected as Lake Charles Boston's Offensive MVP and Defensive MVP along with being selected as the Lake Charles Boston's Offensive Lineman of the Year. Since much of recruiting takes place during a high school player's junior season, Harrison was overlooked by college scouts and wound up without any scholarship offer after his graduation. He enrolled at Northwest Mississippi Community College, but dropped out after the first semester to work as a night stocker at Walmart in Lake Charles. However, he was later recruited to William Penn University, in Oskaloosa, Iowa, by former NMCC assistant coachSteve Miller.
College career
In his freshman year at William Penn, Harrison finished fifth on the team in tackles. As a sophomore and junior, he was voted second-team all-conference. During his senior season, he was recognized as NAIA All-American and first-team all-conference after posting 3.5 sacks and 8.5 tackles for losses among his team-high 60 tackles. Throughout his college career, he started all 44 games he played at William Penn.
Professional career
Prior to the draft, Harrison worked out at Iowa State'spro day, and was “considered a late-round prospect in a weak class of nose tackle.” The last player to have been selected from William Penn in the NFL Draft was Andy Stokes in 2005, who was taken by the New England Patriots with the final pick, and their last player to appear in an NFL game was Warren Loving in 1987. After receiving a seventh-round grade by Jeff Bauer, Jets' director of college scouting, Harrison went undrafted in the 2012 NFL Draft. Right after the draft, he was called by twelve NFL teams to join their practice camp squads.
New York Jets
Harrison was signed by the New York Jets as an undrafted free agent on April 29, 2012. He appeared in 5 games in 2012 but did not record a single stat that year. Following the departure of Sione Pouha and a preseason injury to Kenrick Ellis, Harrison was named the starting defensive tackle for the 2013 season. On October 20, 2013, Harrison recorded his first career sack when he brought down New England Patriots quarterback Tom Brady. During the 2013 season, Harrison started all 16 games making 66 tackles, 2 passes defended, and 1 sack. In 2014, Harrison again started all 16 games with 55 tackles. In 2015, Harrison again started all 16 games making 72 tackles, 0.5 sacks, and a forced fumble.
New York Giants
Harrison signed with the New York Giants on March 9, 2016, to a 5-year contract worth $9.25 million per year with $24 million guaranteed and $30 million over the first three years. With the Giants, Harrison was selected to be in the first team All-Pro by the Associated Press on January 6, 2017. He was also ranked 96th on the NFL Top 100 Players of 2017.
Detroit Lions
On October 24, 2018, Harrison was traded to the Detroit Lions for a conditional 2019 fifth-round draft pick. The condition was that the Lions would give either their own 2019 5th round pick or the 5th round pick that was previously acquired from the San Francisco 49ers in a trade for Laken Tomlinson, depending on which is higher. Because he was traded to the Lions before the Giants bye week and after the Lions bye week, Harrison played in 17 games during the 2018 season, the first defensive lineman to accomplish this feat. On August 21, 2019, Harrison signed a one-year, $11 million contract extension with the Lions, keeping him under contract through the 2021 season. On February 21, 2020, Harrison was released by the Lions.
