Frankie Saenz is of Mexican descent. He began training MMA in 2008. He has a background in wrestling, and wrestled for Arizona State and the University of Northern Colorado; also, holds a blue belt in Brazilian jiu-jitsu. He won WFF Featherweight championship in 2011 at WFF 7, with a TKO win over Michael Parker. Later in the next year, he lost his belt via disqualification to Jeff Fletcher due to an illegal knee to head of grounded opponent. In 2013, Saenz won KOTC Flyweight championship, with a submission win over Marvin Garcia. He defended his belt twice, against Tyler Bialecki and Marvin Blumer.
Ultimate Fighting Championship
After his second title defense on KOTC, Saenz signed with the UFC on August 7, 2014. He was scheduled to make his promotional debut against another newcomer, Nolan Ticman on August 16, 2014 at UFC Fight Night 47. Saenz won the fight via unanimous decision. Saenz later was scheduled to face Aljamain Sterling on November 8, 2014 at UFC Fight Night 55, but the fight was scrapped due to Saenz being injured. On February 22, 2015, Saenz fought Iuri Alcântara at UFC Fight Night 61. As a 7-1 underdog, Saenz defeated the #8 ranked Alcântara via unanimous decision. Saenz faced Sirwan Kakai on August 8, 2015 at UFC Fight Night 73. He won the fight by split decision. Saenz next faced Urijah Faber on December 12, 2015 at UFC 194. He lost the back-and-forth fight by unanimous decision. Saenz faced Eddie Wineland on July 23, 2016 at UFC on Fox 20. He lost the fight via TKO at the 1:54 mark of the third round. Saenz next faced Augusto Mendes on January 15, 2017 at UFC Fight Night 103. He lost the fight by split decision. Both participants were awarded Fight of the Night for their performance. Saenz faced promotional newcomer Merab Dvalishvili at on December 9, 2017. He won the fight by split decision. Saenz faced Henry Briones on May 19, 2018 at UFC Fight Night 129. He won the fight by unanimous decision. Saenz was expected to face Yadong Song on November 23, 2018 at UFC Fight Night 141. However, it was reported on November 7, 2018 that he pulled out of the event due to injury and he was replaced by newcomer Vince Morales. Saenz was scheduled to face Marlon Vera on March 2, 2019 at UFC 235. However, Vera pulled out of the fight on February 27 due to illness and the bout was scrapped from the event. The bout was rescheduled to UFC Fight Night 148. Saenz lost the fight via technical knockout in round one. Saenz faced Jonathan Martinez on August 1, 2020 at. At the weigh-ins, Martinez weighed in at 140.5 pounds, four and a half pounds over the bantamweight non-title fight limit. His bout proceeded at a catchweight and he was fined 30 percent of his purse, which went to Saenz. He lost this fight via TKO in the third round with a knee strike.