Dennis played for the Temple Owls of Temple University from 2007 to 2011. He played in twelve games, starting ten, as a right guard his freshman year in 2007. He played in twelve games, starting six, in 2008. Dennis played in three games, with one start at right tackle, in 2009 before missing the remainder of the season and being redshirted due to a knee injury. He appeared in twelve games, starting two at right guard, one at left guard and four at left tackle, during the 2010 season. He started thirteen games at left guard his redshirt senior year in 2011. Dennis then played in the 2012 East–West Shrine Game. He graduated from Temple in August 2011 with a degree in journalism.
Professional career
Miami Dolphins
Dennis was signed by the Miami Dolphins of the National Football League on May 4, 2012 after going undrafted in the 2012 NFL Draft. He was released by the team on July 26, 2012. His release from the Dolphins was shown on Hard Knocks.
New England Patriots
Dennis signed with the NFL's New England Patriots on August 2, 2012. He was released by the Patriots on August 31, 2012.
Arizona Rattlers
Dennis was assigned to the Arizona Rattlers of the Arena Football League on November 6, 2012. He was exempted on November 29, 2012. He was activated from Other League Exempt on April 7, 2015 and played for the team during the 2015 season, catching three passes for sixteen yards. Dennis was placed on Other League Exempt on October 22, 2015.
Chicago Bears
On November 27, 2012, Dennis was signed to the practice squad of the Chicago Bears' of the NFL. He signed a reserve/future contract with the Bears on December 31, 2012. He was released by the team on August 30, 2013. Dennis was signed to the Bears' practice squad on September 4 and released by the team on September 9, 2013.
Carolina Panthers
Dennis signed with the NFL's Carolina Panthers on January 4, 2014. He was released by the Panthers on August 30, 2014. He was signed to the team's practice squad on September 10, 2014. Dennis signed a futures contract with the Panthers on January 13, 2015. He was released by the Panthers on April 4, 2015.
Calgary Stampeders
On September 21, 2015, Dennis was signed to the practice roster of the Calgary Stampeders of the CFL. He was promoted to the active roster on October 1. He made his CFL debut on October 2, 2015 against the Hamilton Tiger-Cats. Dennis played in five games, all starts, at left tackle for the team during the 2015 regular season. He also started both of the Stampeders' playoff games at left tackle. 2016 was a breakout season for Dennis. He started all 18 regular-season games, 15 starts at left tackle, two at left guard and one at right guard. He was an integral part of a Stampeder unit that allowed the fewest sacks in the CFL in 2016 with 20 and also helped tailback Jerome Messam run for a league-leading 1,198 yards. Because of his accomplishments he was the winner of the CFL's Most Outstanding Offensive Lineman Award.
Saskatchewan Roughriders
On February 14, 2017, Dennis was signed by the Saskatchewan Roughriders. After playing just one season with the team, Dennis was released by the Roughriders on February 13, 2018.
Calgary Stampeders (II)
Three days after his release from the Roughriders, Dennis re-signed with the Calgary Stampeders on February 16, 2018. He started all 18 regular season games and two post-season games for the Stampeders at left tackle and finished the season as a member of the 106th Grey Cup championship team. In 2019 Dennis started 16 game's for the Stampeders, 14 at LT and 2 at RT, and was named a West Division All-Star for a third time in his career. Dennis was not re-signed by the Stampeders following the 2019 season and became a free agent on February 11, 2020.
On February 18, 2020, one week after becoming a free agent, Dennis signed with the XFL as a member of the XFL's Team 9 practice squad. He signed with the New York Guardians on February 25, 2020. He had his contract terminated when the league suspended operations on April 10, 2020.
