Willi Oltmanns first completed an apprenticeship as a decorator. At the age of 18 he started working as a painter in the artists' colony Schreiberhau and became a member of the artist society 'St. Lukas'. In the late 1920s he traveled to Berlin, where he visited Max Pechstein in his studio. Upon his return, he created numerous works influenced by Expressionism. The museums in Breslau and Görlitz acquired some of his paintings.

From 1937 onwards Oltmanns was banned from exhibiting and worked primarily as a stage designer. Finally, he moved to Delmenhorst where he also worked in the field of applied arts and designed murals and stained glass windows. n 1951, the artist regularly participated in the 'Gro...