Conor Anthony McGregor was born in Crumlin, Dublin on 14 July 1988, the son of Tony and Margaret McGregor. He was raised in Crumlin and attended a Gaelscoil and Gaelcholáiste at both primary and at secondary level in Coláiste de hÍde in Tallaght, where he also developed his passion for sport, playing football. In his youth, he played football for Lourdes Celtic Football Club. At the age of 12, McGregor also began boxing at Crumlin Boxing Club, as a way to defend himself against bullies and raise his confidence.

In 2006, McGregor moved with his family to Lucan, Dublin, attending Gaelcholáiste Coláiste Cois Life. Following that, he commenced a plumbing apprenticeship. While in Lucan, he met future UFC fighter Tom Egan and they soon started training mixed martial arts (MMA) together.

On 17 February 2007, at the age of 18, McGregor made his mixed martial arts debut in an amateur fight against Kieran Campbell for the Irish Ring of Truth promotion in Dublin. He won via technical knockout (TKO) in the first round. Following the fight, he turned professional and was signed by the Irish Cage of Truth promotion. In 2008, McGregor began training at the Straight Blast Gym (SBG) in Dublin under John Kavanagh.

On 9 March 2008, McGregor had his first professional MMA bout, as a lightweight, defeating Gary Morris with a second-round TKO. After McGregor won his second fight against Mo Taylor, he made his featherweight debut in a loss via kneebar against submission specialist Artemij Sitenkov. After a victory at featherweight in his next bout against Stephen Bailey, McGregor contemplated a different career path before his mother contacted his coach John Kavanagh and reinvigorated him to continue pursuing mixed martial arts.

In February 2013, UFC president Dana White made a trip to Dublin, Ireland to receive a Gold Medal of Honorary Patronage from Trinity College and was inundated with requests to sign McGregor to the UFC. After a meeting with McGregor, and talking with UFC CEO Lorenzo Fertitta, White offered him a contract days later.

In February 2013, the Ultimate Fighting Championship (UFC) announced that they had signed McGregor to a multi-fight contract. In joining, he became only the second fighter from Ireland to compete for the company, following fellow team member Tom Egan.

On 6 April 2013, McGregor made his UFC debut against Marcus Brimage at UFC on Fuel TV: Mousasi vs. Latifi. McGregor won the fight in round one. The win also earned McGregor his first “Knockout of the Night” award.

McGregor was expected to face Andy Ogle on 17 August 2013 at UFC Fight Night 26, but Ogle pulled out of the bout citing an injury and was replaced by Max Holloway. McGregor won the fight by unanimous decision (30–27, 30–27, and 30–26). Following the bout with Holloway, an MRI scan revealed that McGregor had torn his anterior cruciate ligament (ACL) during the bout and would require surgery, keeping him out of action for up to ten months.

McGregor was expected to face Cole Miller on 19 July 2014 at UFC Fight Night 46 in his comeback bout after recovering from his ACL injury. However, Miller pulled out of the bout citing a thumb injury and was replaced by Diego Brandão. McGregor fought Brandão in front of a loud, rowdy crowd of 9,500 at The O2 in his hometown of Dublin, Ireland. The fight was officially halted by referee Leon Roberts at 4:05 of the first round. The win earned McGregor his first “Performance of the Night” award.

Prior to his next bout, McGregor met with Lorenzo Fertitta and signed a new multi-fight contract with the UFC. McGregor next faced Dustin Poirier on 27 September 2014 at UFC 178. Despite McGregor landing 9 significant strikes to Poirier’s 10, he managed to secure a victory early on in the first round, by pressuring Poirier onto his back foot, before exploding with a left hook behind Poirier’s ear, forcing referee Herb Dean to step in. The finish officially came at 1:46 into the first round. This marked Poirier’s first UFC loss via KO/TKO, and earned McGregor his second straight “Performance of the Night” award.

McGregor faced Dennis Siver on 18 January 2015 at UFC Fight Night 59. McGregor won the fight via TKO in the second round. The victory also earned McGregor his third straight “Performance of the Night” award.

The highly anticipated bout with Aldo was announced on 30 January 2015, at the UFC 183 Q&A. McGregor declared that he was expected to face Aldo on 11 July 2015 at UFC 189 for the undisputed UFC Featherweight Championship, during the UFC’s annual International Fight Week. The fight took place at the MGM Grand Garden Arena in Las Vegas, Nevada. The UFC, confident that the fight would exceed expectations, increased the promotional budget for the event, with company Dana White stating that “[the UFC] spent more money promoting Aldo–McGregor than any fight in UFC history.”

The fight against Aldo was announced on 30 January 2015, at the UFC 183 and both McGregor and Aldo embarked on a 12-day world tour, during which eight cities in five countries were visited, including Aldo’s home country of Brazil (Rio de Janeiro) and McGregor’s hometown of Dublin. The tour began in Rio de Janeiro on 20 March, and completed in Dublin on 31 March. However, on 23 June, it was reported that Aldo had suffered a rib fracture and had pulled out of the bout as a consequence. McGregor remained on the card and was rescheduled to face Chad Mendes for the Interim Featherweight Championship. The official attendance for the event, 16,019, broke the record in Nevada, while the gate of $7,200,000 broke the record for a mixed martial arts event in the United States. Prior to the fight, McGregor’s entrance song, “The Foggy Dew”, was sung live by Irish singer-songwriter Sinéad O’Connor. McGregor won the fight via TKO, winning the UFC Interim Featherweight Championship.

Nevada State Athletic Commission announced the live gate for the event was $55,414,865.79 from 13,094 tickets sold. This was less than the Mayweather vs. Pacquiao fight, which grossed $72 million from a paid attendance of 16,219 in 2015, despite claims from Ellerbe and Mayweather that it did more than $80 million. Sky Sports announced the fight garnered over a million PPV buys in the UK and grossed in excess of £20 million, surpassing the record set in April 2017 when Anthony Joshua defeated Wladimir Klitschko in front of 90,000 at Wembley Stadium. This also meant the fight generated more buys in the UK than Mayweather Jr. vs. Pacquiao. On 14 December 2017, Showtime announced that the fight recorded the 2nd-highest buy rate in the United States and Canada at 4.3 million pay-per-view buys.

After emphatically dispatching Aldo, McGregor continued to express a desire to move up to the lightweight division and attempt to become the first UFC dual-weight champion. On 12 January 2016, the UFC announced that Conor McGregor would face Rafael dos Anjos for the UFC Lightweight Championship on 5 March at UFC 196 (then known as UFC 197). The event would be held at the MGM Grand Garden Arena, in McGregor’s third consecutive headlining appearance at the venue.

On 23 February, it was announced that dos Anjos had withdrawn from the fight after breaking his foot. A variety of competitors at different weight classes were asked to step-in on short notice to face McGregor, including José Aldo, who refused the bout due to a “lack of time” to prepare for it, and former UFC Lightweight Champion and featherweight Frankie Edgar, who turned the fight down due to a groin injury. Instead, The Ultimate Fighter Season 5 winner, and former UFC Lightweight Championship challenger Nate Diaz stepped in to fight McGregor on 13 days’ notice. Initially assumed to be a lightweight contest, McGregor allowed the bout to be contested at 170-pounds, in the welterweight division, to avoid forcing Diaz to cut down to the 155-pound lightweight limit in such little time. On 24 February 2016, a press conference was held to help promote the new main event, with both men trading insults. At the Thursday pre-fight press conference on 3 March, McGregor and Diaz engaged in a brief scuffle during a face-off, after McGregor landed a strike on Diaz’s lead hand. The UFC 196 event, while failing to exceed the gate and attendance records of McGregor’s previous bout, provided respectable numbers, with an attendance of 14,898 and a total gate of $8.1 million. More significantly, the event procured a PPV buyrate of 1,317,000 buys, surpassing McGregor’s own personal record of 1,200,000 for UFC 194.

McGregor will almost always engage in trash talk and “psychological warfare” against his opponents, which has led to comparisons with Muhammad Ali, whom McGregor cites as one of his early inspirations. After Ali died in June 2016, McGregor opined that “nobody will ever come close to [Ali’s] greatness”. McGregor has also cited Bruce Lee as an inspiration, and compared himself to Lee.

After winning the lightweight championship at UFC 205, McGregor announced he would take time off from the UFC to wait for the birth of his first child due in 2017. McGregor spent the majority of his public appearances in early-2017 campaigning for a boxing match with Floyd Mayweather. After months of negotiations, the two finally came to terms on 14 June 2017 and announced the match to take place on 26 August. The match ultimately ended in the 10th round with a victory by TKO for Mayweather.

On 14 June 2017, it was announced that McGregor would compete in his first professional boxing match against the undefeated Floyd Mayweather Jr., on 26 August 2017 at T-Mobile Arena in Paradise, Nevada. The bout was contested at super welterweight (154 pounds) with 8 oz. gloves. The fight was expected to be the richest in boxing history.

On 24 August 2017, it was announced that Mayweather and McGregor would compete for the WBC Money Belt. According to the Nevada State Athletic Commission, Mayweather would earn a guaranteed purse of $100 million and McGregor was guaranteed $30 million.

McGregor has sisters named Erin and Aoife. He has been in a relationship with his fiancé, Dee Devlin, since 2008. Their first child, Conor Jack McGregor, was born on 5 May 2017. Their second child, Croia McGregor, was born 4 January 2019.

In November 2017 McGregor pleaded guilty to exceeding the speed limit in Rathcoole, County Dublin. He was fined €400. In November 2018 he pleaded guilty to speeding in Kill, County Kildare, and was fined €1000 and disqualified from driving for six months.

On 10 November 2017, McGregor’s SBG Ireland teammate Charlie Ward made his debut at Bellator 187 in Dublin against John Redmond. Ward knocked out Redmond in round one, and McGregor jumped the cage (he was not a licensed cornerman) to celebrate Ward’s win while the fight was not yet officially declared over. McGregor was separated by referee Marc Goddard, as Goddard needed to verify if the knockout was before the bell, and to ensure lock down of the cage for medical staff to assess the health of the knocked out Redmond. McGregor charged towards Goddard: while he pushed and confronted Goddard in a wild melee, he also checked on the downed Redmond and knocked him down while he was trying to get up.

McGregor has endorsement deals with Beats by Dre, Monster Energy, Reebok and Bud Light. As of 2017, his endorsement deals rounded up to $7 million. In early 2018, McGregor signed a deal with Burger King.

In September 2018, McGregor launched Proper No. Twelve Irish whiskey in Ireland and the United States. The whiskey is named after the Crumlin neighbourhood in Dublin 12, in which McGregor grew up. McGregor is the founder and owner of the company.

In late 2018, McGregor said that the brand had sold “hundreds of thousands” of bottles since the launch, and plans were to restock in the United States and Ireland in December 2018. McGregor confirmed the brand will extend distribution to the UK, Australia, New Zealand, Russia, and Canada in 2019.

On 3 April 2018, Khabib Nurmagomedov and Artem Lobov had a minor altercation, in which Nurmagomedov cornered Lobov. Lobov is known to be close to McGregor, with whom Nurmagomedov has had altercations and trash talk exchanges. The two groups have a lengthy history of insults and confrontations.

On 5 April 2018, during promotional appearances for UFC 223, McGregor and a group of about twenty others were let into the Barclays Center by credentialed members of his promotional team. They attempted to confront Nurmagomedov, who was on a bus leaving the arena with “red corner” fighters for UFC 223 on it, such as Rose Namajunas, Al Iaquinta, Karolina Kowalkiewicz, Ray Borg, and Michael Chiesa. McGregor ran up alongside the slowly moving bus and then ran past it to grab a metal equipment dolly, which he then threw at the bus’s window, before trying to throw other objects in the vicinity. Chiesa and Borg were injured by the shattered glass and sent to hospital. They were soon removed from the card on the advice of the NYSAC and the UFC’s medical team. Lobov was also pulled from his fight for his involvement in the dispute.

Dana White said there was a warrant out for McGregor’s arrest, and the NYPD said McGregor was a person of interest. White said McGregor had told him via text message: “This had to be done.” “You can imagine he’s going to be sued beyond belief,” White said, and denied suggestions that the violence was a publicity stunt intended to generate interest in the UFC. McGregor and others involved initially fled the Barclays Center after the incident, although he and a fellow accused turned themselves in that night. McGregor was charged with three counts of assault and one count of criminal mischief. He was further charged with menacing and reckless endangerment at his arraignment and released on $50,000 bail until 14 June 2018. Under the bail conditions negotiated by his then attorney, Jim Walden, and set by the judge, McGregor was allowed to travel without restriction. On 12 April 2018, McGregor hired lawyer Bruce Mafeo of Cozen O’Connor to represent him in this matter. McGregor pleaded no contest to a count of disorderly conduct and was ordered to perform five days of community service and attend anger management classes. On 12 September 2018, Chiesa announced a lawsuit against McGregor, saying that he “experienced pain, suffering and a loss of enjoyment of life” as a result of the attack.

Following the fight at UFC 229 on 6 October 2018, Khabib Nurmagomedov jumped out of the cage and charged towards McGregor’s training partner Dillon Danis. Soon afterwards, McGregor and Abubakar Nurmagomedov, Khabib’s cousin, also attempted to exit the octagon, but a scuffle broke out after McGregor punched Abubakar, who then punched him back. Two of Nurmagomedov’s cornermen retaliated: Esed Emiragaev and Zubaira Tukhugov, who was scheduled to fight on 27 October 2018 at UFC Fight Night: Volkan vs. Smith against Artem Lobov, the McGregor team member who was confronted by Nurmagomedov in April 2018. Nurmagomedov’s payment for the fight was withheld by the Nevada State Athletic Commission (NSAC) as a result, pending an investigation into his actions. Nurmagomedov appeared at the post-fight interview and apologised to the NSAC, while also saying that, “You cannot talk about religion. You cannot talk about nation. Guys, you cannot talk about these things. This is very important to me.”

The NSAC filed a formal complaint against both McGregor and Nurmagomedov and on 24 October, the NSAC voted to approve a motion to release half of Nurmagomedov’s $2 million fight payout immediately. Both Nurmagomedov and McGregor received indefinite bans, at least until the official hearing, which took place in December 2018. On 29 January 2019, the NSAC announced a six-month suspension for McGregor, (retroactive to 6 October 2018) and a $50,000 fine. He became eligible to compete again on 6 April 2019.

On 26 March 2019, McGregor announced his retirement on social media. However, Dana White viewed this announcement as a ploy to secure an ownership stake in the company, with White later suggesting his retirement would not last and that he had been in regular contact with him and stated he would fight again in the future. McGregor had previously tweeted that he wanted a rematch with Khabib Nurmagomedov and that he would see him in the Octagon.

In March 2019, The New York Times reported that McGregor was under investigation by the Irish police, following allegations of a sexual assault on a woman in a Dublin hotel in December 2018. A second allegation of sexual assault was reported on in October 2019, regarding an assault on a woman in a car alleged to have taken place earlier that month.

On 11 March 2019, McGregor was arrested outside of the Fontainebleau Hotel in Miami Beach, Florida after an altercation in which McGregor was alleged to have taken a man’s phone and smashed it on the ground. McGregor was arrested and charged with strong-armed robbery and criminal mischief. McGregor was held in custody for several hours before being released on a $5,000 bond. On 14 March 2019, news surfaced that McGregor was also facing a civil lawsuit from the fan involved in the incident. On 8 April, the civil lawsuit against McGregor was dropped by the fan. On 13 May, it was revealed that the criminal charges against McGregor had also been dropped after the accuser’s attorney said that his client had “been made whole” by McGregor following an out-of-court settlement, the accuser stated that he no longer felt that McGregor wished to harm him or the phone, and the State Attorney stated the accuser “has credibility issues as he’s changed his previously sworn testimony”.

On 15 August 2019, TMZ Sports published a video that showed McGregor punching a man at The Marble Arch Pub in Dublin. The incident happened on 6 April and was originally reported by Irish media, although without the video that showed the attack. The Gardaí stated in April that they had opened an investigation. McGregor was charged with assault and first appeared in court on 11 October 2019. On 1 November, McGregor pleaded guilty to the assault and was fined €1,000.

After over a year away from the Octagon, McGregor faced Donald Cerrone in a welterweight bout on 18 January 2020 at UFC 246. He won the fight via technical knockout 40 seconds into the first round. This win earned him a Performance of the Night award. The win made McGregor the first UFC fighter to hold knockout finishes in the featherweight, lightweight, and welterweight divisions.

On 6 June 2020, McGregor announced on social media that he was retiring from fighting.

On 10 September 2020, McGregor was arrested in Corsica on suspicion of attempted sexual assault and indecent exposure for an incident alleged to have taken place in bar. After being held in custody for two days while being interviewed by police, he was released without charge.