Born in Wicklow, Ireland, McShane moved to England when he was 16 to play for Manchester United, with whom he won the 2003 FA Youth Cup.

After four years with Reading, he moved to Rochdale but was released following the COVID-19 pandemic in July 2021, when he made a return to Manchester United as a player-coach for the club's under-23s team.

[14] McShane's first match for the Black Cats ended in success – his performance helping Sunderland to a clean sheet and a 1–0 win over Tottenham Hotspur.

[15] On 29 August 2008, Sunderland accepted a loan offer for McShane from Hull City, who were newly promoted to the Premier League.

[17] His last match during his loan spell for Hull was an FA Cup victory over Newcastle United on 14 January 2009, as he was recalled to Sunderland by manager Ricky Sbragia.

[citation needed] He scored his first goal in over four years on 1 December 2012, shouldering the ball home to help Hull to a 2–1 victory at Nottingham Forest.

[24] More solid performances at the heart of the Tigers' defence followed for McShane in 27 appearances that season, until he was ruled out for the rest of the campaign with ankle ligament damage suffered in a match, again against Nottingham Forest.

[citation needed] With his contract running out at the end of the season, this injury put McShane's long-term future at the club in doubt.

[29] He started the next match, again away at Tottenham but this time in the League Cup three days later, and put in a similarly impressive performance, scoring a header in the 99th minute past a helpless Brad Friedel.

[35] McShane's first goal for Reading came during a 3–1 victory against his former club West Bromwich Albion on 20 February 2016, where he scored the equaliser during the FA Cup Fifth Round match at the Madejski Stadium.

[39] On 23 July 2021, he returned to former club Manchester United as a player-coach, with the intention of being used as an overage player in under-23s matches while coaching in the youth set-up.

[43] An injury to Andy O'Brien and the suspension of Richard Dunne (the two central defenders that had started the match against Cyprus) meant that McShane was given his first international cap against the Czech Republic on 11 October 2006.

[45] McShane was part of the team that missed out on place at the 2010 FIFA World Cup after being defeated by France in Paris in a play-off, and was the Irish player directly behind Thierry Henry[46] when Henry twice handballed late in extra-time before crossing for William Gallas to score an illegitimate, but accepted, goal.

[47] On 29 May 2012, he was called in from the international wilderness to the Irish UEFA Euro 2012 squad following an injury to Kevin Foley ahead of the tournament.