An accomplished kickboxer and Muay Thai fighter, McSweeney won numerous British, Dutch, European and world titles.

[2] In 2006, McSweeney transitioned to mixed martial arts and moved in with The Ultimate Fighter coach Rashad Evans.

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.

In the semi-finals, McSweeney lost against former IFL Heavyweight Champion Roy Nelson via TKO after getting caught in the crucifix position.

He fought Darrill Schoonover on The Ultimate Fighter: Heavyweights Finale card in Las Vegas, Nevada, on 5 December, winning by TKO in the third round.

[7] McSweeney lost a unanimous decision to former UFC Heavyweight Champion Ricco Rodriguez at BAMMA 5: Daley vs Shirai on 26 February 2011.

McSweeney faced fellow UFC veteran Paul Buentello in a Light Heavyweight bout on 23 August 2013 at Legacy Fighting Championship 22.

He faced Chris Lokteff in his debut at ONE Fighting Championship: Rise of Heroes in May and won via KO due to a flying knee in round 1.

McSweeney faced Hatef Moeil at Mix Fight Championship 26 on 22 June 2019, losing the bout via first-round technical knockout.

[15] In September 2021, McSweeney announced that he had retired from mixed martial arts competition in order to continue his kickboxing career.

[24] On 15 August 2012, he stopped an attempted robbery at a convenience store in Las Vegas by subduing a man armed with a knife.