= Söderhamns FF and Halmstads BK He started his career at Söderhamns FF and was transferred to Halmstads BK in 1998. He made his Allsvenskan debut on 4 October 1998 against AIK. Hansson played as a defensive midfielder and as a central defender and became a key player for the club This resulted in a growing popularity among fans and he became the team"s captain.
= South Carolina Heerenveen In 2002 he moved to the Netherlands to play at Eredivisie side South Carolina Heerenveen.
At Heerenveen he developed as a more consistent player and became a fan"s favourite again. = Stade Rennais On 1 May 2007 he signed a contract at Stade Rennais, playing in Ligue 1.
On 15 May 2010 Hansson announced that he would be leaving the club when his contract expired at the end of the season. = AS Monaco On 4 June 2010 he signed a contract with the Ligue 1 club AS Monaco Football Club. On 30 May 2012, Hansson officially announced, through his agent Fabrice Picot, his retirement as a player.
Hansson also made it into the Swedish national team and was part of their squad during Euro 2004 and the 2006 World Cup.
On 2 June 2007, in the rivalry match against Denmark, he scored his first goal for the national team On 10 June in Euro 2008, he scored his second goal for the national team in the opening match of their campaign, a 2–0 defeat of Greece. In October 2010, Hansson made a brief come back to the national team due to defender Olof Mellberg"s suspension in Sweden"s Union of European Football Associations Euro 2012 qualifier away against the Netherlands on 12 October.
Hansson was an un-used substitute.
Sweden was defeated 4–1. International goals
* Match abandoned, see Union of European Football Associations Euro 2008 qualifier fan attack.