Born on 8 May, 1982, in Poza Rica, Veracruz, Mexico. Jessica "Jag" Aguilar started her MMA career in 2006, when she faced fellow-current UFC fighter Lisa Ellis, at Absolute Fighting Championship.  Aguilar spent the next four years fighting at the regional circuit; acquiring a record of 8-3.

Aguilar was signed on to compete at a Bellator Strawweight tournament. She made it past the Quarterfinals, submitting Lynn Alvarez, late in the first round; but lost her Semifinal bout against Zoila Frausto, via split decision.

Signing with Bellator was a turning point for Aguilar as she would continue to compete against high-level opponents. These included wins against Carla Esparza, at Bellator 46: 2011 Summer Series 1; a redemption victory against Lisa Ellis, at Bellator 58; and two victories against Megumi Fujii, at Bellator 69 and VTJ 3rd.

Aguilar would become the first female fighter to be signed to the World Series of Fighting promotion and was given the opportunity to face Alida Gray for the inaugural WSOF SW title. She made short work of Gray as she forced Gray to tap due to a arm-triangle-choke at 2:35 in Round 1.

Aguilar would continue to defend for belt two more times at WSOF 10: Branch vs. Taylor and WSOF 15: Branch vs. Okami, against Emi Fujino and Kalindra Faria, respectively. Both fights would go to the judges decision, awarding Aguilar a UD.

On 18 May, 2015; a little over a week after celebrating her thirty-third birthday, Aguilar was released from the WSOF in order for her to pursue a career in the UFC.

Shortly after that, Aguilar made her UFC debut against Cláudia Gadelha, at UFC 190: Rousey vs. Correia. After an exciting three rounds, it went to the judges decision and Gadelha was awarded the victory.

Outside of MMA, Aguilar currently manages franchise development for the Boca Tanning Club chain in Florida. She is openly gay and has been living with her girlfriend since 2012. Aguilar currently trains out of American Top Team.