Oskar Hansen was born in 1892 to Oskar II and Josephine Maximiliana in what was then the dual Kingdom of Norway and Sweden. Before coming to America, he served as a merchant seaman, then joined the French Foreign Legion in North Africa where he attained the rank of General of Brigade. In the US he served in the US Army and rose from Private to Major. Upon leaving the Army, he built a home and sculpture studio near Charlottesville, Virginia.
While Hansen wrote on theology, astronomy and the arts, he is best known for his work as a sculptor. His most famous works include the winged figures on Hoover Dam which were commissioned by the US Government Parks Department, and the Star Map, also at the Hoover Dam, which was created in collaboration with The Smithsonian Institution and the US Naval Observatory.
In addition, he carved "The Stallion's Head" from a piece of turquoise which is now in the Smithsonian Gem Collection, and sculpted the bronze image of Liberty which tops the Monument to the Alliance in Yorktown, Virginia.