Carroll was raised in Lucan, Dublin and started playing football with junior club, Home Farm in 1998 and he later moved to Belvedere, where he won the FAI Under-17 Cup at Tolka Park.

[3][4] While at Belvedere he played in a side that included fellow future League of Ireland players Neil Harney, Stephen Traynor, David Lodola, Craig Sexton, Paul Corry, Gary Burke, David O'Connor, Tom O'Halloran, Garvan Broughnall, Sean Skelly and future Pats' teammate Chris Forrester.

[7] Carroll's first goal for St Pat's came in an FAI Cup third-round tie with Crumlin United when he curled in a superb free-kick to make it 3–0, he capped a great night for him by winning the Man of the Match award.

[9] Carroll had his first taste of Europa League action when he came on for the final 18 minutes of the third qualifying round tie away to FC Karpaty Lviv of Ukraine.

[10] Carroll was part of the Pats' side that won the 2010–11 Leinster Senior Cup against Dublin rivals Bohemians, ending the club's trophy drought that went back to 2003.

Carroll was given the 3 shirt by newly appointed manager Liam Buckley when he signed a new two-year contract to keep him at the club until the end of the 2013 season, on 18 December 2011.

Just like the previous season, the Saints won 3–0 with Carroll scoring and getting the FAI Ford Man of the Match award, this time for his excellent play at centre midfield and his cool finish after 12 minutes.

[21] Carroll started the 2012 FAI Cup Final against Derry City on 4 November at the Aviva Stadium but was substituted off early in the game due to injury as the Saints agonisingly lost 3–2 in extra-time.

Carroll's performances in the holding midfielder role impressed supporters and manager Liam Buckley, making him one of the favourites along with Shane McFaul and Greg Bolger to fill the void left by James Chambers who departed to fierce rivals Shamrock Rovers during the transfer window.

Carroll made his 50th appearance for St Patrick's Athletic playing at centre back in a 1–0 win away to Limerick at Thomond Park on 30 March 2013.

On 26 April 2013, it was announced that Carroll had signed for the English Championship side Huddersfield Town for an undisclosed fee believed to be in the region of €150,000, completing the move in July.

[40] He suffered an achilles tendon injury in a Scottish Cup tie with St Mirren in February 2020 that was expected to prevent him from playing for the rest of the season.