He is known foremost for playing two recurring characters on three television series - stableman Hank Miller on Gunsmoke and farmer Fred Ziffel on both Petticoat Junction and Green Acres.

[7] Patterson found plenty of movie work, mainly playing cantankerous types and blacksmiths, hotel clerks, farmers, shopkeepers, and other townsmen, usually bit roles and character parts[4] in Republic Pictures Westerns, and then in popular TV Westerns such as The Cisco Kid, The Adventures of Kit Carson, The Lone Ranger, and Annie Oakley.

He also had small cameo appearances in a number of sci-fi movies by Bert I. Gordon: Beginning of the End, The Amazing Colossal Man, Attack of the Puppet People, and Earth vs.

He made additional TV appearances, including in three episodes of The Twilight Zone[14][15] as well as Perry Mason,[16] Burke's Law, The Untouchables, Judd for the Defense, My Three Sons, and in later years The Mod Squad, Love, American Style, and Highway Patrol.

In 1963, Patterson first appeared in what became a recurring role as farmer Fred Ziffel on the popular CBS rural comedy Petticoat Junction.

He even "talked" (snorted, grunted, and squealed) in a language that everyone in Hooterville seemed to understand except Oliver Wendell Douglas (Green Acres co-star Eddie Albert).

[17][18] According to westernclippings.com "Characters and Heavies" by Boyd Magers, "Ironically, by the time Patterson was doing Green Acres, he was in his late 70s and almost completely deaf, but the producers loved his portrayal so much they worked around his hearing impairment by having the dialogue coach lying on the floor out-of-shot tapping Hank's leg with a yardstick as a cue to speak his line.