Donncha O'Callaghan was born in Cork in 1979. He began playing rugby at Highfield Rugby Club before going on to play for the Christian Brothers College, Cork, side which won the Munster Schools Senior Cup in 1998. In the same year, he played on the Ireland U19 World Championship winning side which included other future stars like Brian O'Driscoll and Paddy Wallace. First capped for Ireland in 2003, he has played more than 80 times for Ireland, forming a formidable second row partnership with Paul O'Connell. He has won both the Heineken Cup and the Magners League twice with Munster and has been on two tours with the British and Irish Lions, having the honour of captaining the Lions against the Southern Kings in South Africa in 2009.
Donncha became a UNICEF Ireland Ambassador in 2009. He married his long time girlfriend, Jenny Harte, in December 2009, and their first child, Sophie, was born in July 2010.