Neil Hamilton was born James Neil Hamilton in Lynn, Massachusetts, in 1899.
He began his career as a magazine model and then joined several local stock theater companies. In 1918, at the age of 19, he made his film debut for Vitagraph Studios.
By 1923, he was co-starring under director D.W. Griffith. By 1924, he had signed on with Famous Players-Lasky (which later merged with Paramount Pictures) and was appearing in leading roles by the end of the decade.
Hamilton made the transition to sound and appeared in more than 115 feature films. His last picture was released in 1971.
Hamilton was an early adopter of television roles, appearing on the small screen as early as 1949. He also appeared in several Broadway productions in the 1940s and 1950s. In the 1960s, he was a regular on the hit TV series Batman (1966-1968).
Hamilton married Elsa Whitmer in 1922. They raised one child.
He died after an asthma attack in Escondido, California in 1984. He was 85 years old.