Olivier Marchal started taking acting lessons when he still was a police officer. He began his career in television, appearing in supporting parts or writing scripts for detective TV series. In 1989 when Yves Rénier resurrected his TV series Commissaire Moulin (1976) he became his partner as scriptwriter, series supervisor and sometimes actor. In 2000 he starred as Commandant Pierre Rivière in his own TV series Police district (2000), written by novelist Hugues Pagan, himself also a former police officer.