[1][2][3] He now works as a directeur sportif for UCI ProTeam B&B Hotels p/b KTM.

[4] Dumoulin rode as an amateur for the TCCT[5] (Tonic cyclo club of Ternay).

He won the national youth championship in 1996, then the espoir (young professional) Paris–Tours and Paris-Auxerre in 2001.

He dropped out of the 2004 Tour de France when he crashed after hitting a dog.

In 2008 he won the third stage after a breakaway of nearly 200 kilometres (120 miles), beating Will Frischkorn and Romain Feillu.