Walter Morten Grunwald (9 December 1934 – 14 November 2018) was a Danish actor, stage director and theatre manager. He was born in Odense, Denmark. Grunwald made his debut in "En blandt mange" in 1961. From 1961 until his death, he was married to actress Lily Weiding. He was known for his role as one the lead roles in the popular series of "Olsen Gang" movies.