Career
Celtic
O'Brien made his debut in a 2–1 victory over Gretna on 7 October 2007, he filled in as a right-back due to all of Celtic's recognised players in that position being injured. = Dunfermline Athletic (loan) O'Brien was loaned from Celtic to Dunfermline Athletic during the 2006–07 season. He made his debut in their 3–2 Scottish Cup victory over Rangers on 7 January 2007.
He scored his first goal in Dunfermline's 4–1 victory over Motherwell on 7 May 2007. = Dundee United (loan) O'Brien joined Dundee United on loan on 31 January until May 2008. Motherwell
On 8 August 2008, O'Brien signed for Motherwell.
O'Brien scored four goals in 64 league appearances for Motherwell, earning selection for the PFA Scotland team of the year in 2009–10. Barnsley
On 7 May 2010, O'Brien signed a pre-contract agreement with English Championship side Barnsley, then under the stewardship of Mark Robins. Although he had quite a hard time settling at Barnsley during his first season, he gradually made himself a fans' favourite due to his tireless energy and workrate.
As of 5 April 2013, O'Brien has scored 5 and assisted 8 goals for the Reds. In May 2014, O'Brien rejected a new contract offer from Barnsley. Coventry City
Jim O'Brien completed a move to Coventry City on 4 July 2014 on a two-year contract.
He made his league debut on the opening day of the 2014/15 season in a 3–2 defeat to Bradford City. He scored a disputed first goal for the club against Sheffield United at Sixfields which has later been credited as an own goal for Blades defender Bob Harris. On 15 February 2016, O'Brien was loaned out to Scunthorpe United on an emergency basis.
Although O'Brien represented the Republic of Ireland at under-19 and under-21 levels, he opted to switch allegiances and represent the nation of his birth, citing a chance to work with Craig Levein, who he also worked with while at Dundee United.
