Cregg started his senior career at Arsenal. However he was on the books of Manchester United in the late 1990s. His first senior Arsenal appearance was made in a 3-1 victory against Everton in the League Cup on November 9, 2004 as an 89th minute substitute for Arturo Lupoli. In all he made three appearances for the Gunners, all of them being in the League Cup. He also became a regular in the Republic of Ireland U19 team.
He joined Scottish Premier League club Falkirk in January 2006. Also known as "Padge" he is a fans favourite because of his appetite for the game and his will to win, along with his fierce tackling ability.