Mooney was educated at St Boniface's Catholic College, Plymouth[1] and graduated from the University of Cambridge (Hughes Hall) in 1996.

[2][3] Mooney began his rugby career with London Irish in 1992, making his debut as a prop against Bath aged 20 years old.

[7] He was a member of the promotion winning team that took London Irish to the English Premiership in 1996,[8] as well as the semi-final of the Pilkington Cup, under the leadership of Sir Clive Woodward.

In 2002, Mooney founded Blue Pencil, an international legal executive search and recruitment company, where he is currently the managing director.

[24] A lifetime member of Cambridge University Rugby Union Football Club (CURUFC), and a donor of the CURUFC's Red Lion Foundation, set up to support rugby players through their studies at the university, Mooney made a charitable donation to fund the Lion's Room in 2013.