O'Brien played college football for the Ball State Cardinals, appearing in 40 games and starting 36. He was an integral piece of the offensive line in 2011, as the Ball State offensive line allowed only 11 sacks all season, 12th lowest in the NCAA.
Cleveland Gladiators O'Brien was not drafted in 2013. He was invited to attend training camp with the New York Giants, but did not sign. He then signed with the Cleveland Gladiators of the (AFL).
O'Brien played in 5 games with the Gladiators in 2013, and 18 games in 2014. Indianapolis Colts On August 7, O'Brien signed with the Indianapolis Colts of the (NFL), after Ben Heenan was waived. O'Brien was waived by the Colts the following day, and re-signed with the Colts on August 10.
He was released on September 5, at the end of the preseason. On October 31, O'Brien signed to the Colts practice squad. He was released on November 10.
O'Brien was again signed to the practice squad on December 29.
