While on loan to St Mirren during the 2005–06 season, Adam was part of the team that won both the Scottish Challenge Cup and First Division, playing in over thirty matches for the Saints.

The loan was made permanent at the start of the 2009–10 season, and Adam became an integral part of the Blackpool side, captaining the team to a play-off victory over Cardiff City which resulted in their promotion to the Premier League.

Adam made an appearance at the start of the 2004–05 season,[7] and then joined First Division club Ross County on loan for the rest of that campaign.

[7] During his spell in Paisley, he again appeared in the 2005 Scottish Challenge Cup Final, however this time he was on the winning side as St Mirren defeated Hamilton Academical 2–1.

After playing for Rangers during a July 2006 pre-season trip to South Africa, including scoring a hat-trick against a Jomo Select side,[11] Adam began the 2006–07 season with the club, and he started in their first league match against Motherwell.

[12] He continued to be a regular for Rangers as the season progressed, and scored his first goal for the club in a 3–2 UEFA Cup win over Livorno on 19 October.

[16] On 16 April 2007, at the end of his first season in the first team, Adam was voted by Rangers fans as the club's Young Player of the Year at an award ceremony.

[24] On 25 February, after serving a three-match suspension, Adam scored twice, including a goal from just inside the halfway line, for the club's reserve team as they beat Accrington Stanley 4–2.

[25][26] Adam scored his first Football League goal for Blackpool in a 2–0 victory over Norwich City at Bloomfield Road on 7 March.

On 6 July 2009, Rangers confirmed that they had accepted a bid from Blackpool and that he was set to sign for the Seasiders the following day, subject to personal terms being agreed.

[33] His competitive debut as a permanent Blackpool player was in a 1–1 draw with Queens Park Rangers at Loftus Road later that month.

[35] In January 2010 he was named in the Press Association's Championship "Team of the Week", along with teammate Neal Eardley, following his performance two days prior, in a 3–2 home victory over Watford.

Adam scored a match-winning penalty against Nottingham Forest in the semi-final first leg,[40] and Blackpool won the tie on aggregate.

In the play-off final, Adam scored a free-kick as Blackpool beat Cardiff City 3–2 at Wembley Stadium and gained promotion to the Premier League.

The panel upheld Adam's complaint, but did not agree with his second argument that the failure to pay the amount constituted a breach of contract on the club's part.

[44] In January 2011, Blackpool rejected a £4.5 million bid from Liverpool to buy Adam, an amount described by manager Ian Holloway as "disgraceful".

[56] Liverpool reached the 2012 Football League Cup Final where they defeated Championship side Cardiff City in a penalty shootout, despite Adam missing his kick.

[66] Adam then spent three months in and out of the team before returning to the starting line up in April and scored the winning goal against Norwich City which eased Stoke's relegation worries.

[71][72] Adam came off the bench to help Stoke to a 2–1 victory over Aston Villa on 21 December 2013 which earned him praise from manager Mark Hughes for his contribution.

[79] On 11 May 2014 Adam scored the winning goal against West Bromwich Albion on the final day of the season which earned Stoke 9th place in the Premier League.

[93] Adam struggled for playing time in 2017–18, making 14 appearances, as Stoke suffered relegation to the EFL Championship.

[94] Adam made two noticeable errors during Stoke failed survival bid as he saw his last minute penalty saved against Brighton & Hove Albion in February and was needlessly sent-off against Everton in March.

[97] Adam struggled for playing time under Gary Rowett in the first half of the 2018–19 season before he was brought back into the squad by Nathan Jones in January 2019, before a calf injury disrupted his comeback.

This was not known to Adams at the time, and stemmed from a mistaken belief by his teammates that he was ingratiating with management when there was drinks break during training.

[107] On 15 September 2020, after training on his own and having considered an offer to play in Australia, Adam joined his boyhood club Dundee on a two-year deal, which he described as being a "dream" of his.

[108][109] In an interview with FourFourTwo, Adam stated he believed Dundee would be his final club, due to his age and happiness at Dens Park.

[112] After a successful start to his time with the Dee, during which he was made captain, Adam was awarded the SPFL's Championship Player of the Month for December.

[120] Adam sustained a groin injury in a Premiership match against Motherwell in August 2021, and despite avoiding surgery he was ruled out for six weeks.

[130] Adam was called up by national manager Alex McLeish to the Scotland squad for the first time on 11 May 2007 for a friendly against Austria and a Euro 2008 qualifying Group B match against the Faroe Islands.

[141][142] On 23 January 2025, Adam was confirmed as the set-piece coach at Everton as part of David Moyes's new backroom team.