The writer passed away in Brentwood, Los Angeles last Friday following a lengthy battle with Alzheimer's disease, according to Reuters.
Denoff began working for television in the early days of the medium, contributing to the influential comedy programme Your Show of Shows and Bob Hope Presents The Chrysler Theater.
He would go on to write and serve as a story consultant for the Dick Van Dyke Show, later reuniting with Dick Van Dyke for a one-off television special.
The two-time Emmy Award-winning Denoff teamed with Bill Persky to create the sitcom That Girl, in which Marlo Thomas starred as an aspiring actress for five seasons from 1966 to 1971.
In his later years, Denoff worked as an advisor and part-time writer on It's Garry Shandling's Show and Life with Bonnie.
Denoff is survived by his wife Sharon and his four children.
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Watch the intro to That Girl below: