Trimble was born in Robbinston, Maine, and in 1908 he sold an animal story to a magazine in New York. The magazine referred him to Vitagraph Company to write a story about making films. Trimble became a member of the Vitagraph company and both he and his dog Jean were employed as actors. His dog became Jean the Vitagraph Dog, the first canine to have leading part in motion pictures.
Jean died in 1916 and Trimble and his wife Jane Murfin found another dog on a trip to Germany. They purchased a German shepherd police dog named Etzel von Ceringen that would become more successful. They changed his name to Strongheart (1917-24 -1929) and he became the first major canine film star.
Trimble ended his film career in 1926 and died in 1954 in Woodland Hills, California.