 Billborn was appointed assistant coach Brommapojkarna's senior team in 2010, first working with manager Kim Bergstrand and then Roberth Björknesjö.Before the start of the 2014 season, Billborn was promoted to head coach at Brommapojkarna.The club finished 16th and last in the Allsvenskan table, only claiming 12 points in 30 games.