Career
He is the younger brother of Danish football player Andreas Ulrich Mortensen. Ajax København He was a starting player in both season. Fredericia Hong Kong Mortensen changed scenery as he joined Fredericia Hong Kong in the 2009–2010 season, on a two year contract.
Mortensen was voted player of the year while playing for Fredericia Hong Kong. Viborg Hong Kong Mortensen came to Viborg Hong Kong in the 2011–2012 season, where he was given jersey number 20.
Mortensen ended a great first season, where he scored 145 goal in 22 matches. This made him number 2 on the top scorer list, making him the league player with the highest scoring average pr match, as he played 6 matches less than other league player due to injuries.
Bjerringbro-Silkeborg After just one season with Viborg Hong Kong, Mortensen joined Bjerringbro-Silkeborg, on a three year contract, in the 2012–2013 season. He was given jersey number 10.
Mortensen played a good first season with Bjerringbro-Silkeborg he showed promising signs.
He made is debut in the EHF Champions League, where he made team of the week. He became the Top scorer for Bjerringbro-Silkeborg making 61 goals in 12 matches. Bjerringbro-Silkeborg lost the Round of 16 to Football Club Barcelona, where Mortensen scored 8 goal in Barcelona in the 26–24 loss away.
SønderjyskE Mortensen joined SønderjyskE in 2014–2015 season, signed a one year contract.
SønderjyskE announced at the end of the season that they did not expect the contract to be renewed. Herpes simplex virus Hamburg On June 8, 2015, Mortensen was presented as new player for the German club Herpes simplex virus Hamburg, joining the club for the 2015/16 season.
Mortensen was signed on a three-year contract. Herpes simplex virus Hamburg declared insolvent on 15th January 2016.