Hellström began his career with Väsby United, but he played just 12 times between 1997 and 1999 before departing to join Hammarby but again first-team league appearances were limited as he appeared in 7 matches. 2003saw him move to Assyriska, a move that proved to be a success as he featured in 102 games from 2003 and 2006. In 2007, Hellström left Assyriska and rejoined Hammarby but left the latter two years later after only appearing in six matches. During his last year with Hammarby, he joined again with Väsby Unitedon loan but made just two appearances. He officially retired in 2011.