Although he was Danish, Willumsen lived almost half of his life in France. His sculpture The Great Relief (completed 1928) was included in the 2006 Danish Culture Canon as one of Denmark"s cultural masterpieces. Willumsen had associations with Skagen in the north of Jutland which he first visited in 1906.
lieutenant was here that he carried out most of the preparatory work on his painting Badende børn på Skagen strand (Children bathing on Skagen beach) which he completed in 1909.
Willumsen was an influence for Kitty Lange Kielland, who attempted to simplify her art in order to follow his style. There are also paintings by Willimsen in the collection of the ARoS Aarhus Kunstmuseum in Aarhus, Denmark.
He was awarded the Prince Eugen Medal in 1947.