[4] He started his career at several clubs in Sweden, winning consecutive Allsvenskan titles with Djurgården before moving to France where he represented Rennes and Lyon.

Källström left Spartak in 2015 to join Grasshoppers, where he had a 49 game long spell before ending his career at Djurgårdens IF together with close friend Andreas Isaksson.

[10] In his first season at Djurgården, Källström won the double of the Allsvenskan and the national cup tournament Svenska Cupen, and was the team's top scorer with twelve league goals.

[17] After a successful spell at Rennes, Källström signed for Lyon in June 2006, and went on to win a number of honours with the southern club.

[14] His Lyon debut saw him score the equalising goal as les Gones won the Trophée des Champions against Paris Saint-Germain on penalties.

[19] After ending the group stage unbeaten – including a defeat of nine times champions Real Madrid at the Stade de Gerland[20] – Lyon were knocked out in the round-of-16 by Roma.

[21] On 22 October, Källström scored his first Ligue 1 goal for the club in a 4–1 Choc des Olympiques derby defeat of Marseille at the Stade Vélodrome.

[22] He scored further goals in league wins against Saint-Étienne[23] and Nancy[24] as Lyon won the French championship for the sixth consecutive season.

[26] The 2007–08 season began with Valencia rumoured to be interested in signing Källström from Lyon, who wanted to keep the player despite the €13 million offer.

[35] On 16 November 2008, Källström scored his first goal of the 2008–09 season in a 2–1 win over championship rivals Bordeaux to put Lyon seven points clear at the top of the Ligue 1 table.

[44] Källström scored in a 4–0 win at Hungarian champions Debreceni[45] and made eleven appearances overall, helping les Gones reach the semi-finals where they lost to Bayern Munich.

[15] In the Coupe de France, he scored one goal and assisted another as Lyon knocked out Paris Saint-Germain with a 3–1 win at the Parc des Princes at the quarter-final stage.

[58] He played in all of Spartak's 2012–13 UEFA Champions League group matches, receiving a red card in a 2–1 defeat at Celtic on 5 December 2012.

[61] Källström made his debut for Arsenal on 25 March against Swansea City in the Premier League, coming on in the 79th minute as a substitute for Tomáš Rosický.

[68] After three years in Russia, Källström left Spartak and signed for Swiss Super League club Grasshoppers on 6 June 2015.

[70] After one and a half years, Källström wanted to leave Grasshoppers, citing personal reasons and dissatisfaction with the club's results.

[73] After playing 28 league games in 2017, scoring three goals and providing seven assists, Källström announced his retirement from football on 15 December that year.

In a 2014 World Cup qualifier against Germany on 16 October 2012, Källström was brought on as a substitute for Pontus Wernbloom at half time with Sweden losing 3–0.

[78] In the return match against Germany, Källström comforted Max, a team mascot who suffers from Williams Syndrome, and a photo of this went viral on social media.

He said: "Because of your actions, Kim, my son could experience precisely the same emotions as everyone else who has been a mascot: pride, a sense of being special, 'I did it' and an immense joy.