American film director and screenwriter.

He graduated from Drake College, worked as a newspaper reporter and actor in vaudeville and theater. During World War I, he began working in films and became a prolific director and screenwriter, working on many silent westerns by William S. Hart, Buck Jones, Tom Mix and others.

Often associated with producer Thomas H. Ince, Hillyer expanded into romantic melodramas and crime films in the 1920s. In 1936, he directed two chillers for Universal, the sci-fi film The Invisible Air and the cult horror Dracula's Daughter. He directed the first film portrayal of Batman, a 15-part serial produced in 1943 that was re-released as a feature film in 1965.

He directed many B movies for Columbia Pictures in the 1930s and early 1940s, including westerns which were his specialty.

Hillyer finished his career directing low-budget dramas and westerns for Monogram Pictures. In the early days of television, he also directed an episode of the syndicated western, The Cisco Kid. He directed at least one episode of Highway Patrol, which starred Broderick Crawford.