Joey attended Drimnagh Castle primary and secondary school were he was a keen sportsman. Joey played hurling for the school team in primary school and in sixth class he reached the hurling final which was played in Croke park and which drimnagh castle went on to win. They were playing against St.Marks from Tallaght. Joey was also an ever present member of the Drimnagh castle secondary school football team where he was a success and an inspiration to the upcoming players in the school.
To gain further experience, O'Brien was loaned out to League One team Sheffield Wednesday for the most part of the 2004-2005 season, making 15 appearances and scoring two goals, including one on his debut. O'Brien was named as captain for the last game of his loan spell in honour of his contribution.
O'Brien is in the current Bolton squad for 2007/2008.
Upon returning to Bolton, O'Brien made his Premiership debut in May 2005 against Everton F.C. when coming on as a late substitute in place of Fernando Hierro. He was given his first start in Bolton's colours in their away UEFA Cup 1st Round tie with Lokomotiv Plovdiv in September 2005. O'Brien missed most of the 2006/2007 season due to injury, however he has since made his return for Bolton and played most of the 2007-2008 season in his natural midfield role as opposed to the right back position which he had been used two years previous.
In July 2008 he was given the number 8 shirt previously worn by Ivan Campo.
He made his debut for his country on the 1st of March 2006