Mein's father, Lee Mein, began operating a local promotion called Rumble in the Cage. It gave Mein, who had been training since the age of four, his first fighting opportunity and when he was just 11 years old he fought another local boy in a kickboxing match. That fight helped start Mein's fighting career that has included kickboxing tournaments, Brazilian jiu-jitsu competitions, at both the amateur and professional level.
Jordan's first amateur fight came when he was 14, and he compiled a 6–0–1 record before turning professional. He turned professional at the age of 16 in June 2006 at one of his father's Rumble in the Cage shows. Jordan defeated Joe Riggs via second round KO at Wreck MMA: Strong and Proud on January 28, 2011. He fought UFC veteran Josh Burkman at MMA 1: The Reckoning on April 2, 2011. He won via unanimous decision.
Strikeforce
Mein signed a four-fight deal with Strikeforce in July 2011 and made his promotional debut at, defeating Evangelista Santos via TKO in the third round. Mein fought Tyron Woodley at. He lost a split decision. Mein defeated Tyler Stinson at via unanimous decision.
Score Fighting Series
Jordan fought Dream Welterweight Champion, Marius Žaromskis at Score Fighting Series 1 on June 10, 2011 Winning via unanimous decision. Mein fought Forrest Petz in the main event of the Score Fighting Series 7 on November 23, 2012. He won via TKO early in the first round.
Ultimate Fighting Championship
Mein made his UFC promotional against Dan Miller on March 16, 2013 at UFC 158. He won the fight via TKO in the first round. Mein made a quick return to the Octagon as he faced Matt Brown on April 20, 2013 at UFC on Fox 7, replacing an injured Dan Hardy. He lost the fight via TKO in the second round, after a Brown knee fractured his nasal and orbital bones. Despite the loss, the back-and-forth bout earned him his first Fight of the Night bonus award. Mein was expected to face Santiago Ponzinibbio on April 19, 2014 at UFC on Fox 11. However, Ponzinibbio was removed from the bout and was replaced by Hernani Perpetuo. He won the fight via split decision. Mein was expected to face Thiago Alves on August 23, 2014 at UFC Fight Night 49. However, Alves pulled out of the bout citing a knee injury and was replaced by Brandon Thatch. Subsequently, Thatch also pulled out of the bout with Mein citing a toe injury. Mein would instead face Mike Pyle after Pyle's scheduled opponent at the event, Demian Maia, also pulled out with an injury. He won the fight via first round TKO. The win also earned Mein his first Performance of the Night bonus award. The bout with Alves eventually took place on January 31, 2015 at UFC 183. Despite dominating the first round on the feet, Mein lost the fight via TKO in the second round after Alves landed a kick to the body. In August 2015, Mein announced that he had retired from MMA competition. In September 2016 Mein was tested by the United States Anti-Doping Agency as part of the UFC anti-doping program suggesting a return to competition. Returning from his nearly two-year sabbatical, Mein faced promotional newcomer Emil Weber Meek at UFC 206. He lost the fight via unanimous decision. Mein faced Belal Muhammad on July 8, 2017 at UFC 213. He lost the fight by unanimous decision. Mein faced Erick Silva on December 16, 2017 at. He won the fight by unanimous decision. As the last fight of his prevailing contract, Mein faced Alex Morono on July 28, 2018 at UFC on Fox 30. He won the fight by unanimous decision.
Bellator MMA
On January 7, 2020 it was reported that Mein was signed with Bellator MMA. He made his promotional debut against Jason Jackson at Bellator 242 on July 24, 2020. Mein lost the bout via unanimous decision.
