Diarmuid O'Sullivan (born 27 July 1978) is an Irish hurling coach and hurler who plays for Cork Premier Championship club Cloyne. He played for the Cork senior hurling team for 12 years, during which time he usually lined out as a full-back. A fan favourite who was noted for his swashbuckling style during his inter-county career, O'Sullivan is considered a "Cork legend".
O'Sullivan began his hurling career at club level with Cloyne, for whom his father Jerry O'Sullivan, had also played. He broke onto the club's top adult team as a 16-year-old in 1995 and enjoyed his greatest success two years later when the club won the 1997 Cork Intermediate Championship title and promotion. O'Sullivan has made 90 championship appearances in three different grades of hurling for the club, while his early prowess also saw him selected for the Imokilly divisional team with whom he won the 1997 Cork Senior Championship.
At inter-county level, O'Sullivan was part of the successful Cork under-21 team that won back-to-back All-Ireland Championships in 1997 and 1998. He joined the Cork senior team in 1997. From his debut, O'Sullivan was ever-present as a defender and made a combined total of 110 National League and Championship appearances in a career that ended with his last game in 2008. During that time he was part of three All-Ireland Championship-winning teams – in 1999, 2004 and 2005. O'Sullivan also secured five Munster Championship medals and a National Hurling League medal as captain of the team. As a dual player at the highest level, he won a Munster Championship medal with the Cork senior football team in 2002. O'Sullivan announced his retirement from inter-county hurling on 12 May 2009, instead opting to transition to rugby, where he had stints with Cork clubs Highfield and Midleton.
O'Sullivan was named Young Hurler of the Year in 1999 while he also won his first All-Star that year. He claimed a further three All-Stars in 2000, 2004 and 2005. At inter-provincial level, O'Sullivan was selected to play in five championship campaigns with Munster, with his sole Railway Cup medal being won in 2000.
O'Sullivan was born in Cork and raised in Cloyne in East Cork. His father, Jerry O'Sullivan, played with the Cloyne club from the 1960s until the 1990s before later serving as an administrator with the Cork County Board and the Munster Council. O'Sullivan's brother, Paudie, has also been a member of the Cork senior hurling team.
During his secondary schooling at Midleton CBS Secondary School, O'Sullivan was more renowned as a Gaelic footballer before joining the college's senior hurling team. On 26 March 1995, he was at right wing-forward on the Midleton CBS team that defeated Lismore CBS by 3-18 to 3-05 to win the Harty Cup title. O'Sullivan lined out on the Midleton CBS senior hurling team for a further two years. He later said: "I found Harty hurling much tougher than minor inter-county. The games were of an intensity that I had never previously encountered. You became aware very quickly of the standard required to compete and you had to adapt to the various styles played by schools from the different counties. It toughened me up a fair bit and stood to me in my later career with Cork."
O'Sullivan joined the Cloyne club as a seven-year-old and played in all grades at juvenile and underage levels. Speaking of his first hurling appearance he said: "I went on not knowing what I was leaving myself in for but I knew when I came off I wanted more of it." O'Sullivan was first selected for the club's intermediate team in 1995.
On 20 October 1996, O'Sullivan was at left wing-back when Cloyne drew with Newtownshandrum in the final of the Cork Intermediate Championship. He lined out in the same position a fortnight later when Cloyne were defeated in the replay by 0-12 to 0-09.
O'Sullivan lined out at left wing-back in his second successive final on 2 November 1997. A 1-12 to 1-07 defeat of Delanys secured the title and a Cork Intermediate Championship medal for O'Sullivan.
On 31 October 2004, O'Sullivan was at right wing-back when Cloyne qualified to face Na Piarsaigh in the final of the Cork Senior Championship. He was switched to centre-back during the game and scored a point from as free, however, Cloyne were defeated by 0-17 to 0-10.
Cloyne qualified for a second successive Cork Senior Championship final with Newtownshandrum providing the opposition on 16 October 2005. O'Sullivan lined out at centre-back in the 0-15 to 0-09 defeat.
O'Sullivan was appointed captain of the Cloyne team for the 2006 championship, while he also took up a new position at centre-forward. On 22 October 2006, he captained the team when they were defeated by 2-19 to 3-14 by Erin's Own in the Cork Senior Hurling Championship final.
O'Sullivan had just turned 18 when he was first selected for the Imokilly divisional team. He was a regular in the half-back line throughout the 1996 championship and was at left wing-back when Imokilly drew with Avondhu in the final on 22 September 1996. A fortnight later he was selected in the same position for the replay which Imokilly lost by 0-13 to 1-08.
O'Sullivan was again selected at left wing-back the following year. On 5 October 1997, he won a Cork Senior Championship medal after a 1-18 to 2-12 defeat of Sarsfields in the final.
In spite of Harty Cup success as well as being added to the Cloyne intermediate team, O'Sullivan was disappointed not to be selected for the Cork minor team in 1995. He later said: "I was overlooked...it was a fair kick. I was disappointed. I suppose when you look back there's always some bit of politics. Somebody looking after their own." O'Sullivan was called up to the minor panel the following year, making his only appearance on 26 June 1996 in a 0-16 to 1-09 defeat by Tipperary in the Munster Minor Hurling Championship.
O'Sullivan subsequently progressed onto the Cork under-21 team and won a Munster Championship medal at full-back on 30 July 1997 following a 1-11 to 0-13 defeat of Tipperary. He was at full-back again for the subsequent 3-11 to 0-13 All-Ireland final defeat of Galway on 21 October.
On 23 August 1998, O'Sullivan won a second successive Munster Championship medal after a 3-18 to 1-10 defeat of Tipperary in the final. He later won a second successive All-Ireland Championship medal at full-back on 20 September after a 2-15 to 2-10 defeat of Galway.
O'Sullivan was just eighteen-years-old when he made his first appearance for the Cork senior team on 23 March 1997. He was selected at left corner-back for the 4-21 to 2-11 defeat of Antrim in the National Hurling League. O'Sullivan was later selected at left corner-back for Cork's 12-19 to 0-18 Munster Championship defeat by Clare on 8 June. At the end of the season he was regarded as unlucky not to have been nominated for an All-Star.