|Height||1.75 m (5 ft 9 in)|
14 July 1984|
|Wins by KO||20|
Gary "Spike" O'Sullivan (born 14 July 1984) is an Irish professional boxer who has formerly held the WBO International and Irish middleweight titles. He has also acted and has performed stunts in the 2007 film Strength and Honour. O'Sullivan is a member of Murphy's Boxing, a boxing promotion founded by Ken Casey of the Boston punk band Dropkick Murphys.
O'Sullivan vs. Hall
O'Sullivan vs. Nunez
It was announced following this defeat of Larry Smith that O'Sullivan would take on former world contender Milton Nunez. O'Sullivan, before the fight, described the bout as "the most important fight of my life". He started the fight well with some solid body shots easily claiming the first round. He knocked Nunez down in the second round and ultimately scored an impressive victory, by TKO, over Nunez in the third round.
O'Sullivan vs. Douglas
After a loss to Chris Eubank Jr., O'Sullivan won four straight fights to earn a December 2017 bout against rising prospect Antoine Douglas on HBO. While the fight was meant to be a showcase for Douglas, O'Sullivan won a gritty battle by seventh round knockout.
O'Sullivan vs. Lemieux
After beating Berlin Abreu on the 4th of May, it was announced that O'Sullivan would be fighting on the undercard of Canelo Álvarez vs. Gennady Golovkin II on the 15th of September. A fight with David Lemieux, a fight that Spike had previously chased in recent years, was mooted but O'Sullivan seemed reluctant to give Lemieux the fight as he had previously turned it down himself. However, after weeks of back and forth verbal jousting online, the fight was officially made with both fighters declaring that they will knock the other out and many tipping it as a potential fight of the night. 
In 2010 O'Sullivan was convicted of assaulting his ex-partner and fined €300.This conviction was later overturned after appeal January 2011.
Professional boxing record
|31 fights, 28 wins (20 knockouts), 3 losses|
|Loss||28–3||David Lemieux||KO||1 (12)||2018-09-15||T-Mobile Arena, Paradise, Nevada|
|Win||28–2||Berlin Abreu||RTD||3 (10)||2018-05-04||StubHub Center, Carson, California|
|Win||27–2||Antoine Douglas||TKO||7 (10)||2017-12-16||Place Bell, Laval, Quebec, Canada||Won vacant WBO Inter-Continental middleweight title|
|Win||26–2||Nick Quigley||TKO||4 (10)||2017-09-30||House of Blues, Boston, Massachusetts|
|Win||25–2||Chauncey Fields||KO||2 (8)||2017-05-13||Plainridge Park Casino, Plainville, Massachusetts|
|Win||24–2||Ronald Montes||TKO||3 (8)||2017-03-18||House of Blues, Boston, Massachusetts|
|Win||23–2||Jaime Barboza||UD||8||2016-09-17||Bank of New Hampshire Pavilion, Gilford, New Hampshire|
|Loss||22–2||Chris Eubank Jr.||RTD||7 (12)||2015-12-12||The O2 Arena, Greenwich, London||WBA Middleweight title final eliminator.|
|Win||22–1||David Toribio||KO||2 (10)||2015-10-10||Lowell Memorial Auditorium, Lowell, Massachusetts|
|Win||21–1||Melvin Betancourt||KO||2 (10)||2015-05-23||Agganis Arena, Boston, Massachusetts|
|Win||20–1||Milton Núñez||TKO||3 (8)||2015-03-14||Madison Square Garden, New York City, New York|
|Win||19–1||Larry Smith||TKO||2 (6)||2015-02-26||Memorial Hall, Melrose, Massachusetts|
|Win||18–1||Anthony Fitzgerald||TKO||1 (10)||2014-11-15||3Arena, Dublin|
|Win||17–1||Jose Medina||MD||6||2014-06-05||House of Blues, Boston, Massachusetts|
|Loss||16–1||Billy Joe Saunders||UD||12||2013-07-20||Wembley Arena, Wembley, London||Lost WBO International Middleweight Title.|
|Win||16–0||Tadas Jonkus||TKO||3 (8)||2013-05-03||Carlton Hotel Tyrrelstown, Dublin||Retained WBO International Middleweight Title.|
|Win||15–0||Matthew Hall||UD||12||2012-07-14||Upton Park, West Ham, London||Won vacant WBO International Middleweight Title.|
|Win||14–0||Paul Morby||PTS||6||2012-03-10||Braehead Arena, Glasgow|
|Win||13–0||Robert Long||TKO||1 (10)||2011-06-25||National Stadium, Dublin||Retained Irish Middleweight Title.|
|Win||12–0||Ryan Clark||KO||1 (4)||2011-05-21||O2 Arena, Greenwich, London|
|Win||11–0||Sylvain Touzet||TKO||3 (6)||2010-06-26||Neptune Sports Arena, Cork|
|Win||10–0||Ciaran Healy||PTS||10||2009-12-14||Neptune Sports Arena, Cork||Won vacant Irish Middleweight Title.|
|Win||9–0||Arturs Jaskuls||PTS||6||2009-07-25||National Basketball Arena, Dublin|
|Win||8–0||Marcin Piatkowski||KO||1 (6)||2009-04-25||Silver Springs Moran Hotel, Cork|
|Win||7–0||Jimmy LeBlanc||DQ||4 (8)||2009-03-14||Dorchester Armory, Dorchester, Massachusetts|
|Win||6–0||Idiozan Matos||TKO||3 (6)||2008-10-26||Gleneagle Hotel, Killarney|
|Win||5–0||Sergejs Volodins||RTD||1 (6)||2008-09-13||Neptune Sports Arena, Cork|
|Win||4–0||Eugen Stan||PTS||6||2008-07-05||National Basketball Arena, Dublin|
|Win||3–0||Tye Williams||TKO||1 (4)||2008-04-15||National Stadium, Dublin|
|Win||2–0||Robert Harris||TKO||1 (4)||2008-03-15||Orpheum Theater, Boston, Massachusetts|
|Win||1–0||Peter Dunn||TKO||6 (6)||2008-01-26||Neptune Sports Arena, Cork||Professional debut.|
- Strength and Honour (2007, stunts)
- The Last Round (2012, short film, as Opponent)
- The Vein Within (2013, as Steven Murphy)
- "Irish Examiner Column April 24 2009". Michael Moynihan's Irish Sportsblog. 28 May 2009. Retrieved 5 December 2015.
- "Cork Boxer Gary 'Spike' O'Sullivan to fight on Boston Card". IrishCentral. Retrieved 20 May 2015.
- http://www.murphysboxing.com/#!roster/c1jo3 Archived 7 January 2016 at the Wayback Machine.
- "Gary 'Spike' O'Sullivan beats Matthew Hall at Upton Park".
- "Spike O'Sullivan interview: meet the latest Irish boxer in search of a world title". The Guardian. 11 March 2015.
- "Cork's Spike O'Sullivan grabs TKO win at New York's iconic Madison Square Garden". the42.ie. 15 March 2015.
- "Saunders vs Lemieux results: Spike O'Sullivan stops Antoine Douglas in seven". BadLeftHook. Dec 16, 2017.
- "Spike O'Sullivan v David Lemieux finally made OFFICIAL". Irish-Boxing.com. Aug 21, 2018.
- Haylin, Liam (10 July 2010). "Mahon boxer convicted of punching ex-partner". Irish Examiner. Retrieved 11 September 2018.
- Gary O'Sullivan's Professional Boxing Record. BoxRec.com. Retrieved 1 June 2015.