Mogens Lorentzen graduated college in 1910 and studied medicine before he was trained as a painter. After that, he worked both as a painter and author. He débuted as an expressionistic painter in 1916 and was a member of the artist group Grønningen from 1930-39. In later years he developed a more lyrical form. As a writer he published a series of poems and short stories beginning in 1927.
Lorentzen’s big breakthrough was when he started his monthly series of the radio program "Then ..". His novel The Family Gelinde was also very popular and was made into a film in 1944. Mogens Lorentzen contributed to show Poul Henningsen's revues and wrote songs like Christmas Tree with its Decorations and Mother Denmark and the revue ballad It's Fun to be With. He had many stays and travels abroad.