Born in Cork, Ireland, but raised in London, England, McSweeney started kickboxing when he was six years old. At 15, he left school and moved to Thailand to train full-time in Muay Thai. An accomplished kickboxer and Muay Thai fighter, McSweeney won numerous British, European and World titles. In 2006, McSweeney transitioned to mixed martial arts and moved in with The Ultimate Fighter coach Rashad Evans. The two quickly struck up a bond after McSweeney helped prepare Evans for his bout against Forrest Griffin in December 2008. While training for his fight against Travis Browne, McSweeney switched his camp from Jackson's Submission Fighting in Albuquerque, New Mexico to the Grudge Training Centre in Denver, Colorado to train full-time along with fellow UFC competitors Shane Carwin, Brendan Schaub and Nate Marquardt. McSweeney recently moved out of the Grudge Training Centre to return to the tutelage of European Muay Thai legend Lucien Carbin and to open up his own gym Sledgehammer MMA in Kent, England.
''The Ultimate Fighter''
McSweeney was on The Ultimate Fighter: Heavyweights fighting alongside Team Rashad. McSweeney was the first overall pick and fought on the second episode of the show against Wes Shivers defeating him via majority decision. McSweeney moved on to the next round of the tournament, fighting teammate, Matt Mitrione. McSweeney won via guillotine choke in the first round. In the semi-finals, McSweeney lost against former IFL Heavyweight ChampionRoy Nelson via TKO after getting caught in the crucifix position.
McSweeney was given another chance by the UFC despite losing on The Ultimate Fighter. He fought Darrill Schoonover on card in Las Vegas, Nevada, on 5 December, winning by TKO in the third round. McSweeney made his second appearance for the UFC on preliminary card, fighting against undefeated newcomer Travis Browne. The fight ended in a TKO victory for Browne due to punches at 4:32 of the first round. McSweeney claims he was hit with illegal elbows and briefly tried to appeal the loss. McSweeney later decided against the appeal to focus on his next fight instead. McSweeney was to drop to the Light Heavyweight division at UFC 120 to fight Tom Blackledge. However, McSweeney would instead face Fábio Maldonado after Blackledge was forced to pull out of the bout. McSweeney lost the bout in the third round via TKO due to punches. As of 20 January 2011, conversations over McSweeney's Twitter account were strongly indicative that he is no longer a part of the UFC.
Independent Promotions
McSweeney lost a unanimous decision to former UFC Heavyweight ChampionRicco Rodriguez at BAMMA 5: Daley vs Shirai on 26 February 2011. He then had a further loss to submissions ace Francisco France in April 2011 at a Crowbar MMA event. Fighting on 22 July 2011, Mcsweeney defeated Lee Mein by TKO in the 1st round. On 20 August 2011, McSweeney defeated Sam Brown by Submission in the 1st round. McSweeney faced former MFC Light Heavyweight ChampionEmanuel Newton at Superior Cage Combat 3. He lost by submission in the first round. McSweeney faced fellow UFC veteran Paul Buentello in a Light Heavyweight bout on 23 August 2013 at Legacy Fighting Championship 22. He lost the fight via TKO in the second round.
In 2014, McSweeney signed with the Asian promotion ONE Championship. He faced Chris Lokteff in his debut at in May and won via KO due to a flying knee in round 1. In his second fight for the promotion, McSweeney faced Cristiano Kaminishi at in August. He again won the fight via KO in the first round. For his third fight with the promotion, McSweeney faced Roger Gracie at in December. He lost the fight via TKO in the third round.
KSW
McSweeney was expected to face Polish prospect Michal Andryszak at on 6 October 2018. However, Andryszak was pulled from the event due to injury and was replaced by Thiago Silva. McSweeney lost the fight by unanimous decision.
