Aldo made his professional MMA debut on August 10, 2004, as part of EcoFight 1, knocking out his opponent via head kick in 18 seconds. He would win nine of his next 10 fights across nine MMA promotions, including Pancrase, Shooto Brazil and Jungle Fights, before joining WEC in 2008.
Jose made his U.S. debut on June 1, 2008, on the prelims of WEC® 34: FABER vs. PULVER, which took place at ARCO Arena in Sacramento, Calif. He defeated former Shooto lightweight champion Alexandre Nogueira via TKO (punches) in the second round. Jose would win his next four WEC fights via knockout, earning him his first title shot against champion Mike Brown.
WEC® 44: BROWN vs. ALDO took place on November 18, 2009, at The Pearl at the Palms Casino in Las Vegas and served as Aldo’s first headlining event as a professional mixed martial artist. Brown entered the main event as the undisputed WEC featherweight champion with a 22-4 record and a 10-fight winning streak over three years.
Aldo, who entered the match on an eight-fight winning streak of his own, used his speed, kicks, flying knees and takedown defense to control the fight until mounting and ending the bout two minutes into the second round to become the new WEC featherweight champion.
Jose would win his next nine fights, defending the title each time and pushing his winning streak to an impressive 17 over eight years. During his title reign, he would serve as the final WEC featherweight champion and become the inaugural UFC featherweight champion in 2010, as the organization was absorbed by Zuffa.