 Just before the Norwegian transfer window closed in March 2012, Fredrik joined Lillestrøm on a season-long loan-deal.His contract with Vålerenga was terminated ahead of the 2013 season, and Stoor subsequently signed a one-year contract with Lillestrøm.On January 23, 2014, Frederik Stoor signed a 6 months contract with Danish Superliga club Viborg FF, on a free transfer

A full Swedish international in 2008, Stoor was part of the squad that took part in UEFA Euro 2008 and has made 11 appearances for Sweden so far.