He studied art at the Cologne University of Applied Sciences, graduating in 1974 after a short-term exchange in New York with Howard Kanovitz and Larry Rivers.

He remains an active painter who both designs most of the covers of the BAP albums and holds exhibitions of his work.

He was one of the initiators of the 1992 event Arsch huh, Zäng ussenander (literally: Get off your arse and open your mouth), an open-air concert in Cologne against racism.

Niedecken played a live concert with the band Bläck Fööss in the Millowitsch-Theater in Cologne.

Niedecken and Leopardefell were also the backing musicians on Bruce Springsteen's hit "Hungry Heart" when it was re-released in 1995 and featured in the video which was shot in a bar in Berlin.