After graduating from the Leipzig High School, Ellerhusen came to the United States in 1894 and became a United States citizen six years later. He studied under Lorado Taft at the Art Institue of Chicago, and under James Earle Fraser and Gutzon Borglum at the Art Students League in New York. He also attended the Cooper Union, and worked with Karl Bitter from 1906 to 1912. He taught sculpture at the Beaux-Arts Institute of Design, New York, for eight years, and at the Entwistle School of Art in Ridgefield, New Jersey.
One of Ellerhusen's early commissions, the Peace Monument in East Orange, New Jersey, brought his work to the attention of the public and led to further commissions. He made a speciality in sculpting religious works and monuments honoring American pioneers. His The March of Religion, a series of twenty-one statues for the south facade of the University of Chicago Chapel, won the Architectural League's Gold Medal in 1929. In 1933 he collaborated with architect Francis Keally on the monument, First Permanent Settlement of the West for Pioneer State Park, Harrodsburg, Kentucky. That same year, his relief panel, Atomic Energy, was unveiled at the Chicago World's Fair. He designed the Schwab Memorial Fountain at Yale University, New Haven, Connecticut, and his statue, Oregon Pioneer, sits atop the Oregon State Capitol. A model of the latter work was shown at the National Academy in 1939. Ellerhusen also executed the architectural and religious sculpture which adorns the entrance to the Church of the Heavenly Rest, the building immediately next door to the present home of the Academy.
Ellerhusen began exhibiting at the Academy in 1910 and continued to do so until his death. He served as a member of the Council from 1940 to 1943. He was also a member of the National Sculpture Society, the Allied Artists of America, the Salmagundi Club, and New York's Municipal Arts Society, among others. In 1921 he married the successful portrait painter, Florence E. Cooney.
