In his active career, Christensen played for Danish clubs AB and Lyngby BK,3 as well as French club AS Saint-Etienne and FC Aarau from Switzerland.4 He debuted for the Danish national team in 1982, and he played a total of 11 national team matches and scored 2 goals. He was selected to represent Denmark at the 1986 World Cup, but did not play any matches.
After ending his active career, he became a football manager, and among other teams managed Slagelse B&I, Næstved BK, AB, and ÍF Fuglafjørður.
"Danske VM-minder: Laudrup, Elkjær, superstjernerne og vi andre". tipsbladet.dk. https://www.tipsbladet.dk/nyhed/vm/danske-vm-helte-superstjernerne-og-vi-andre ↩
"Samme opskrift". bt.dk. https://www.bt.dk/nyheder/ab-samme-opskrift ↩
"Lyngby-Boldklub.dk - Topscorere". Archived from the original on 25 January 2010. Retrieved 15 February 2010. https://web.archive.org/web/20100125232842/http://lyngby-boldklub.dk/Information/Historie/Topscorere/ ↩
"..:: National Football Teams ::.. Player - Flemming Christensen". Archived from the original on 14 July 2011. Retrieved 15 February 2010. https://web.archive.org/web/20110714155730/http://nationalsoccerteams.com/v2/player.php?id=37501 ↩