Claim: Conor McGregor officially started his mixed martial arts career in 2008 after being released from prison.

Conor Anthony McGregor -LRB- Irish : Conchúr Antóin Mac Gréagóir ; born 14 July 1988 -RRB- is an Irish professional mixed martial artist who is currently signed to the Ultimate Fighting Championship -LRB- UFC -RRB- . He is the reigning UFC Lightweight Champion , and former UFC Featherweight Champion . During his career , McGregor has competed as a featherweight , lightweight , and welterweight .   In 2008 , McGregor started his mixed martial arts -LRB- MMA -RRB- career and , in 2012 , he won both the Cage Warriors Featherweight and Lightweight Championships , holding both titles concurrently before vacating them to sign with the UFC . In 2015 , at UFC 194 , McGregor defeated José Aldo for the UFC Featherweight Championship via knockout thirteen seconds into the first round . This was the fastest victory in UFC title fight history . Upon defeating Eddie Alvarez for the UFC Lightweight Championship at UFC 205 , McGregor became the first fighter in UFC history to hold titles in two weight divisions simultaneously .   He is known for being the biggest pay-per-view draw in MMA history , as well as his extravagant lifestyle and trash talking .