Markus Siewert started his musical career in a boys' choir in the Philarmony of Suhl, Germany. At the age of 16 he started funded vocal studies and wrote his own songs. The TV of the GDR produced two Videoclips, of which one was forbidden right after the first broadcast. But the other one is still aired in matter of 80's music in the GDR. From 1987 until 1989 he was the singer of the pop-project "Speed", who were very popular in the former GDR.
Although he had big success the resentment against the GDR, the system, the politic and the suppression of free thought, began to grow. 1988 he filed an application of deprivation of citizenship which was allowed on the 9. november 1989 the day before the Fall of the Wall. Markus wrote a book "IM Techno" about his time and experiences as an artist in the GDR.
His first releases appeared surprisingly only in 1994 on DIVISION Records. With the Projekt DJ MO vs. Marc de Clarq he succeeded the first placements in the german Dance Charts. With a release on VANDIT Records under the Project M.M.d.C. he stays in the Top 20 Dance Charts for 6 weeks. As a DJ he shares the stage with the big names of the scene, such as Paul van Dyk, Marusha and Westbam.
Since 2006 Marc de Clarq is predominantly working as a producer for newcomers in the pop-scene. Together with Arne Northern he founded Sample Records in 2007. In addition he writes Trailer-Music for the television.