In 2009, Palomino fought for Bellator Fighting Championships, where he competed in their Featherweight Tournament.
Palomino began his career with 3–0 record, in the Absolute Fighting Championship promotion, one of which being a victory over future The Ultimate Fighter 7 competitor Jeremy May via unanimous decision.
Palomino's next six fights ended via KO/TKO, whether he won or lost. During this stretch, Palomino had a record of 4–2.
In his final fight prior to joining Bellator, Palomino fought John Mahlow for the XFC Lightweight Championship, in a bout that was featured on the Inside MMA show. Palomino lost the fight via submission (rear naked choke) in the fifth round.
Palomino then joined Bellator to take part in their Bellator Season One: Featherweight Tournament. His opening round fight was against Estevan Payan at Bellator 1. Palomino was knocked down by Payan and almost submitted with a rear naked choke in the first round, but time expired before Payan could finish the fight. The next two rounds were regarded as difficult to score and this led to the verdict of a split decision (29–28, 28–29, 29–28) which didn't go Palomino's way.
Despite his elimination from the featherweight tournament, Palomino stayed with the Bellator promotion and continued in the featherweight division. His opponent at Bellator 6 was Nick Gonzalez and Palomino defeated him via TKO (punches) in the second minute of the first round.
Palomino next faced Troy Gerhart at Bellator 12 in a 150 lb bout and defeated him via unanimous decision (29–28, 29–28, 29–28).
After the first season of Bellator ended, Palomino took a few fights outside of the promotion. Palomino lost his first fight to eventual The Ultimate Fighter winner Jonathan Brookins via submission (rear naked choke) in the second round. Palomino followed the loss up with two victories including wins over Rafael Dias by TKO and Jorge Masvidal via split decision.
In his next Bellator appearance at Bellator 21, Palomino defeated Jose Figueroa via unanimous decision in a lightweight bout.
Palomino then stayed with Bellator into the third season. His first fight of the season was against Yves Edwards at Bellator 24, which he lost via unanimous decision.
Palomino signed with local promotion Championship Fighting Alliance, Palomino quickly made his CFA debut on May 6, 2012 in Miami, Florida against Peter Grimes for the inaugural CFA Featherweight championship at CFA's inaugural event; CFA: The Title. Palomino defeated Grimes by submission due to an armbar at 4:59 of round 4.
Palomino returned at CFA 04: Izquierdo vs. Cenoble on December 17, 2011 in Coral Gables, Florida against well known journeyman Charles Bennett. Palomino was able to use his speed advantage to counter punch the aggressive Bennett and ultimately knocked Bennett out at 3:59 of the first round. Palomino became only the second man to knock Bennet out.
Palomino was scheduled to fight former Maximum Fighting Championship Lightweight Champion Antonio McKee at CFA 06 on April 13, 2012 in Coral Gables, Florida . McKee was forced off the card due to an injury and was replaced by James Warfield, the fight was originally scheduled for the CFA Lightweight Championship but Warfield did not make the required weight of 155 pounds thus re-scheduling the fight to a non-title bout. Warfield knocked Palomino down in the first round but Palomino was able to recover and control the rest of his fight by using his unorthodox and fast striking to pick Warfield thus winning by unanimous decision.
Palomino next faced 2x Hero's Grand Prix winner and Strikeforce veteran Gesias Cavalcante at CFA 07: Never Give Up on June 30, 2012 in Coral Gables, Florida. Palomino became the first man to ever finish Cavalcante and he did so via third round knockout due to punches.
Palomino returned to action at CFA 09 on January 19, 2013 when he faced PRIDE veteran Luiz Firmino for the CFA Lightweight Championship, Palomino lost a unanimous decision after being constantly outgrappled and taken down throughout the fight.
Palomino bounced back from his previous defeat on May 24, 2013 at CFA 11 by knocking out Robert Washington in the first round.
Palomino faced The Ultimate Fighter 8 winner Efrain Escudero at CFA 12 on October 12, 2013. He lost the bout via unanimous decision.
Palomino made his WSOF debut on January 18, 2014 in Hollywood, Florida against Jorge Patino, Palomino won via second round knockout.
Palomino faced champion Justin Gaethje for the WSOF Lightweight Championship at WSOF 19 on March 28, 2015. He lost the back-and-forth fight via TKO in the third round.
Palomino faced Gaethje in a rematch on September 18, 2015 at WSOF 23. It was again a back-and-forth battle that Palomino lost via TKO in the second round.
Palomino next entered WSOF's one night Lightweight tournament to determine the number one contender for the Lightweight Championship. He faced Rich Patishnock in the quarter finals and won via knockout in the first round. He then faced Brian Foster in the semifinals and lost via TKO in the second round.
Palomino faced Chechen fighter Musa Khamanaev on January 13, 2017 at ACB 51. He won the fight via TKO in the second round.
In the second fight he faced Marcos Vinicius Schmitz on May 20, 2017 at ACB 61. He won the fight via unanimous decision.
Palomino faced Yusuf Raisov on August 19, 2017 at ACB 67. He lost the fight via unanimous decision.Xtreme Fighting Championships
XFC Featherweight Championship (One time)
Championship Fighting Alliance
Championship Fighting Alliance Featherweight Championship (One time; First)
2012 Championship Fighting Alliance Most Valuable Fighter
Knockout of the Night (Two times) vs. Gesias Cavalcante on June 30, 2012 and vs. Charles Bennett on December 17, 2011
2015 March Fight of the Month vs. Justin Gaethje
2015 September Fight of the Month vs. Justin Gaethje
2015 Best Fight of the Half-Year vs. Justin Gaethje
Promoted to black belt on April 25, 2012 by Daniel Valverde