Born in San Francisco. Married Lole Louise Ligny in 1908. They had one child. Married Joan Louise Bruning. They had a son. Served as a captain in the U.S. Army during WW I. Studied at the Mark Hopkins Institute of Art in San Francisco and taught at Mark Hopkins 1901 to 1904. He worked in Paris 1904 to 1907. Later he taught at the Art Students League. He was a director of the National Academy of Design.

Aitken sculpted monuments and architectural features. His best known work was the west pediment of the U. S. Supreme Court Building.

He designed these commemorative coins:

Panama-Pacific Exposition $50 round and octagonal 1915-S

Missouri Centennial half dollar 1921 California-Pacific International Exposition (San Diego) half dollar 1935

He won a contest and $1000 to design the official medal (HK 399-401) struck by the mint at the Panama Pacific Exposition in San Francisco.

He died at home in New York City.

bio: ApCAB; CCUS; Fielding; NCAB 15; P-F; WWWA 2; WWWAmArt, obit NYT 1/4/49