Strongheart became the first major canine film star. Trimble trained the dog and directed him in four rugged outdoor adventure pictures that were shot on location: "The Silent Call" (1921), "Brawn of the North" (1922), "The Love Master" (1924) and "White Fang" (1925). The partnership between Trimble and Murfin faltered; after their breakup, Strongheart's death and the loss of most of his investments in the Wall Street Crash of 1929, Trimble retired from filmmaking and trained animals exclusively. He was able to keep McDonald Island, an island he had purchased on the Saint Lawrence River, and in February 1930 he began writing an occasional feature "about dogs, horses, and other people" for "The American Boy" magazine.