Ejnar Hansen, painter, muralist, sculptor, and printmaker, was born Niels Ejnar Hansen in Copenhagen, Denmark on 9 January 1884. He attended the Teknisk Skole and the Royal Academy of Art in Copenhagen between 1903 and 1910 while supporting himself as a journeyman painter. Hansen was a member of the secessionist group De Tretten (The Thirteen), which advocated modernist art.

In 1914, at the age of thirty-years-old, Hansen immigrated to the United States and arrived on 7 June. He lived in Michigan and Wheaton, Illinois and exhibited in annual exhibitions at the Art Institute of Chicago. He moved west to California and settled in Pasadena in either 1924 or 1925 and became a naturalized citizen on 2 April 1925. He taught at the Otis Art Institute, the Chouinard Art Institute between 1937 and 1940, Pasadena City College, Pomona College, John Muir College, and the Pasadena School of Fine Arts in 1952.

Hansen was a member of and exhibited with the Los Angeles Art Association, the California Art Club, the California Watercolor Society, and the Pasadena Society of Artists. His work is represented in the permanent collections of the Laguna Beach Art Museum, California and the Los Angeles County Museum of Art, California.

Ejnar Hansen died in Pasadena on 26 September 1965.