After retiring as a player he joined his former club, TPS, as an assistant coach in 2003. He took charge of the first team as a caretaker in 2008 after
Martti Kuusela's dismissal. After the appointment of
Pasi Rautiainen in 2009, Allen became the manager of TPS's
feeder club,
ÅIFK as well as the youth teams of TPS. In November 2009 Allen signed a two-year contract with
RoPS, then playing in the
second highest division of Finnish football system. After only one season with RoPS they gained promotion to
Veikkausliiga after being crowned the champions of Ykkönen. In October 2014 he was signed by FC Jazz. Allen joined Swedish team
Oskarshamns AIK in December 2018, where he lasted as headcoach until April 2020. In May 2020, he returned to TPS as an assistant coach of the club's
women's team. ==Honours==