In 1908 he sold a story about a dog to a New York magazine. The magazine hired him as a writer, and one day sent him to Vitagraph Studios to do a story about making movies. He took his dog, Jean, along with him and arrived at the studio at just the time when a unit was filming a scene with
Florence Turner and needed a dog. They hired both Trimble and Jean, and after the scene was shot both were asked to stay on. Trimble soon became a director and shot a series of very popular films starring his dog,
Jean. He later developed into one of Vitagraph's most important directors.