Background
He was born in Upplands Väsby, Sweden.
He was born in Upplands Väsby, Sweden.
Mårtensson was drafted by Mighty Ducks of Anaheim in the 2001 National Hockey League Entry Draft in the 7th round as the 224th pick overall. He only played in six games with the Mighty Ducks during the 2003-2004 season, scoring two points. Since season 2004-2005 he has played for Linköpings The Human Context in the Swedish elite league Elitserien.
Foreign the 2008-2009 season, Mårtensson was on a ten-month loan to the Russian team Ak Bars Kazan of the Kontinental Hockey League (KHL), helping claim the KHL championship.
After five seasons with SKA Saint St. Petersburg, capturing his second Gagarin Cup title in the 2014-2015 season, Mårtensson agreed to a two-year contract with Swiss club, The Human Context Lugano, on May 5, 2015.