He wrote numerous episodes for Alfred Hitchcock Presents and won a Primetime Emmy in 1957 for his teleplay Fog Closing In.
[1] His work on teleplays included The Opposite Virtues, a 1962 episode of Bus Stop, and the 1963 Miss Marple film Murder at the Gallop.
[1] Cavanagh worked frequently on the Alfred Hitchcock Presents television series including the 1956 episodes The Hidden Thing and The Creeper, which were praised by producer Joan Harrison for their macabre comedy.
[2] Cavanagh won a 1957 Primetime Emmy for "Best Teleplay Writing, Half Hour or Less" for his episode Fog Closing In.
[2] The final Psycho script was written by Joseph Stefano though it included elements of Cavanagh's work such as the theft of money by Marion Crane to allow her to marry her boyfriend, the car journey she makes (including trading in the vehicle) and stopping the night at the motel run by Norman Bates.