His debut was Så møtes vi imorgen (1946), and he broke through with the comedy Vi gifter oss (1951). Later films include Kvinnens plass (1956), Det store varpet (1960), Tonny (1962), Elskere (1963) and Broder Gabrielsen (1966). Det store varpet was entered into the 2nd Moscow International Film Festival.
He directed 21 films in total, and was awarded in 1996.
Müller was the brother of the Stalag Luft III Prisoner Of War escapee Jens Müller.