Jensen began training at the age of 15, under UFC 3 winner Steve Jennum. Following his first fight against Travis Fulton in February 1997, he did not compete again until June 2002. Jensen quit his day job in November 2006, and has been training and fighting full-time since then.
His UFC debut was on August 25, 2007 at UFC 74; his initial opponent was supposed be Travis Lutter, however Lutter was forced to withdraw due to injury. Instead, Jensen faced late replacement Thales Leites and after a strong start, got caught by an armbar submission in the first round. He followed this up with another loss to Demian Maia before leaving the UFC. On March 29, 2008, Jensen accepted a fight against Joey Villasenor on four days notice in the Strikeforce promotion. Again, after a strong start, Jensen lost by KO with 15 seconds remaining in the first round at. Since then, Jensen rebounded with a first round TKO over Mitch Whitesel at SportFight 23 in June 2008, as well as a first round submission victory over Aaron Praschack due to strikes in VFC 23. Jensen then returned to the UFC and was defeated by Wilson Gouveia at via submission. This was followed up by a win over Steve Steinbeiss at via first round technical submission. Jensen faced Mark Muñoz at UFC 108 on January 2, 2010. He lost the fight via submission at the 2:30 mark of the first round. Jensen faced Jesse Forbes at UFC 114 on May 29, 2010. He defeated Forbes by guillotine choke submission in the first round. Jensen fought Court McGee at UFC 121. He lost the fight via arm triangle choke in the third round. Jensen was defeated by Jason MacDonald via first round submission at UFC 129 and was subsequently released from the promotion.
Post-UFC
One year after his UFC release, Jensen returned to MMA and faced Jason Louck at Disorderly Conduct: Warriors on May 19, 2012. He won the fight via guillotine choke submission. He then faced Rudy Bears in the main event of Victory Fighting Championship 39 on March 30, 2013. Jensen won the fight via first round TKO. Jensen faced Victor Moreno at Victory Fighting Championship 40 on July 27, 2013. He won the fight via guillotine choke submission. Jensen then faced Ryan McClain at Victory Fighting Championship 42 on March 15, 2014. He won the fight via first round TKO.
After compiling a 4-0 record on the regional MMA circuit, Jensen made his Bellator MMA debut on April 18, 2014 at Bellator 117. He defeated Mark Stoddard by submission in the first round.
