[3] A full international between 2008 and 2021, Larsson represented Sweden at the 2008, 2012, 2016 and 2020 editions of the UEFA European Championship, as well as the FIFA World Cup in 2018, at which he helped his country reach the quarter-finals.

[4] Having been on the substitutes bench for a match against Panathinaikos, he made his first-team debut against Manchester City in the League Cup on 27 October 2004, where he played out of position at left back.

[5] He made his Premier League debut on 1 February 2006, replacing Sol Campbell at half time as Arsenal lost 3–2 at home to West Ham United.

Recalled to the starting eleven by new manager Alex McLeish for the game at Tottenham Hotspur in December 2007, Larsson scored a spectacular stoppage-time goal to give Birmingham their first away win in the Premier League for over three months.

[19] With four weeks of the season remaining, Opta statistics rated Larsson as the most accurate taker of a direct free kick in the Premier League,[20] though this ability failed to save Birmingham from relegation.

On the opening day of the 2010–11 season, Larsson recovered from what the Observer's reporter described as an "anonymous" start to provide assists for both Birmingham's goals as they drew 2–2 with Sunderland at the Stadium of Light.

[22] Away to Fulham on 27 November, Alexander Hleb made "a terrific run"[23] and a "slide-rule" pass to Larsson, who opened the scoring with his first goal of the season, a low shot across the goalkeeper.

[26] Despite speculation over his future at Birmingham – with his contract due to expire at the end of the season, his advisor was given permission to talk to Newcastle United about a proposed move during the January transfer window, but personal terms were not agreed,[27] and the player was booed when he came on as a substitute in the previous game, against Manchester United[28] – Larsson returned to the starting eleven in place of the cup-tied David Bentley[29] and played 100 minutes as Birmingham overturned a 2–1 deficit to win the semi-final 4–3 on aggregate.

[30] Roger Johnson flicked on Larsson's corner for Žigić to give his team an unexpected lead in the final at Wembley against firm favourites Arsenal.

[31] Larsson took advantage of a defensive mix-up to open the scoring as Birmingham beat Sunderland 2–0 at St Andrew's on 16 April,[32] and four days later, marked his 200th appearance for the club in all competitions with a penalty, albeit in a losing cause, against reigning champions Chelsea.

[33] On 1 May, he exploited Michael Mancienne's mistake to score the equalising goal against Wolverhampton Wanderers, helping his side earn a point despite playing with ten men for more than an hour after Gardner was sent off.

[35] On 22 June 2011, Sunderland confirmed that Larsson would join the club on a free transfer under the Bosman ruling on 1 July,[36] thus linking him up with former Birmingham manager Steve Bruce.

[37] He marked his debut with the second-half equaliser in a 1–1 draw on the opening day of the season against Liverpool at Anfield, when given room at the far post to produce a "superb first-time angled volley.

"[citation needed] His second Sunderland goal, direct from a free kick, put his team 4–0 up against Stoke City at the Stadium of Light in their first win of the season.

[47] The strike against West Ham proved to be Larsson's only goal of the campaign, a season in which was underwhelming on both individual and club levels as Sunderland barely managed to avoid relegation.

[51] On 16 August 2014, Larsson scored a late equaliser for Sunderland in their 2–2 draw with West Bromwich Albion on the opening day of the 2014–15 Premier League season.

[61] His first season with AIK was very successful, as he helped the team win the Swedish Championship for the twelfth time in the club's history after claiming the 2018 Allsvenskan title.