A professional from 2007 until 2014, he competed for the UFC, ShoXC, and was the winner of the first season of the television show Pros vs Joes.

Brenneman earned his Bachelor of Arts in Secondary Education/Spanish from Lock Haven University, and returned to his hometown to teach Spanish at his former high school for three years, which is where his nickname 'the Spaniard' came from.

[4] He continued his education, earning his Master of Arts from East Stroudsburg University of Pennsylvania in Sports Management.

He was unexpectedly cast after submitting his application to participate in the reality game show, but he won the competition alongside his older brother Ben.

[5] Following his victory on the Pros vs. Joes show, Brenneman resigned from his high school teaching job to pursue a mixed martial arts fighting career.

Brenneman also earned a 5–0 record at the professional level through early 2008, with a notable split-decision victory over Drew Puzon at the ShoXC event on January 25, 2008.

[6][7] During a sparring session with one-time UFC fighter Chris Liguori, Brenneman sustained a kick to the face that shattered his left orbital and forced him to undergo emergency surgery to repair the damage.

[9] However, just hours before the weigh-ins it was reported that Nate Marquardt did not receive medical clearance and had to pull out of his bout against Rick Story.

[10] Brenneman lost to Anthony Johnson via first-round TKO due to a head kick on October 1, 2011 at UFC Live: Cruz vs.

Brenneman faced Erick Silva on June 8, 2012 at UFC on FX 3 and lost via rear-naked choke near the end of the first round.