As Vice President of Affliction, a clothing company founded in August 2005, Tom Atencio helped made it popular. Affliction seized an opportunity after observing the growth of Mixed Martial Arts (MMA) made possible by UFC, sponsoring some of its fighters. A self-described longtime fan of MMA, Atencio made his professional MMA debut in 2005, fighting in Total Combat. He defeated David Martinez by unanimous decision. Affliction made an apparel deal with UFC heavyweight champion Randy Couture, who was embroiled in a contract dispute with UFC. This lead to Dana White ending Affliction's sponsorship of UFC fighters. A similar ban was enacted by Gary Shaw, the President Of Live Events for the Elite XC (2007) promotion. Shaw predicted that Affliction would leave the fight promoting business after two events. Affliction created Affliction Entertainment in 2008 to promote MMA events, and in May 2008 announced its first MMA event with Tim Sylvia and Fedor Emelianenko in the the main event.
In response to Affliction: Banned (2008) airing on Pay-Per-View on July 19, 2008, UFC scheduled UFC: Silva vs. Irvin (2008) on Spike TV at the same time. "Banned" was noted for its high fighter payroll of over $3.3 million while taking in comparatively little revenue through Pay-Per-View and arena attendance. On January 24, 2009, Affliction promoted Affliction: Day of Reckoning (2009) headlined by Fedor Emelianenko and Andrei Arlovski. Similar to Affliction: Banned (2008) , Affliction: Day of Reckoning (2009) had a fighter payroll of over $3 million which surpassed revenues from ticket sales and Pay-Per-View. While Affliction planned it's third event titled "Trilogy", Atencio prepared for his second MMA bout. Atencio delegated some of his duties to focus on competing, while Tracy Hess and Rafael Cordeiro prepared him against Randy Hedderick in Fight Force International. Atencio won by technical knockout by way of retirement. Atencio resumed his full duties for Countdown to Affliction: Trilogy (2009) with Josh Barnett set to challenge Fedor Emelianenko for the WAMMA Heavyweight championship in the main event. The bout was canceled after Barnett failed a drug test administered by the California State Athletic Commission. Soon after the entire event was canceled. Affliction left the fight promotion business and was welcomed back by UFC. Atencio later said that fighters' managers exploited Affliction's ignorance to negotiate extremely high salaries for their clients. Furthermore, Atencio suggested that Barnett knew in advance that he may fail a drug test and didn't inform Affliction in time for them to get a replacement against Emelianenko.