McGregor would become the second fighter from Ireland to compete under the UFC after Tom Egan. His UFC debut did not disappoint- he would win by knockout in the first round and would also earn him his first “Knockout of the Night” award.
He would continue to silence any competition in glorious fashion, knocking out UFC favorites such as Diego Brandao, Jose Aldo, Nate Diaz, and Dustin Porier, whom he would face again in what would later become one of the most popular trilogies in the sport.
It was also during this time that McGregor earned a reputation as the greatest trash-talker of the sport, his swag and hubris a testament to his undeniable dominance in the octagon.
McGregor would eventually become the first UFC fighter to hold two UFC championships in two weight classes simultaneously.
In 2017 he entered the boxing ring to face Floyd Mayweather Jr. The bout reportedly made McGregor $130 million despite losing via TKO in the tenth round.
He would would return to the UFC a year later and become the biggest draw in UFC history with 2,400,000 pay per view purchases in his bout with Khabib Nurmagomedov in 2018.