Born Martin Ingerman in Brooklyn in 1936, Ingels got his start acting in the early 60s, appearing in numerous television roles including his own short-lived sitcom I’m Dickens, He’s Fenster, with John Astin. Among his other television roles, he guested on The Dick Van Dyke Show, Bewitched, The Love Boat, and in 2010, on CSI.
Ingels appeared in several films during his career, including Armored Command (1961), A Guide for the Married Man (1968), If It’s Tuesday, This Must Be Belgium (1967), and Instant Karma (1990). He also worked steadily as a voice actor, voicing several classic cartoons. Among his roles were Beegle Beagle in The Great Grape Ape Show, AutoCat in the Autocat and Motormouse cartoons which aired as part of The Cattanooga Cats and their own series, and as Pac-Man on the 1980s animated series.
Later in life Ingels worked mainly as a talent agent, representing actors for celebrity endorsements.
Ingels married The Music Man and The Partridge Family star Shirley Jones in 1977. The couple published an autobiography about their relationship, Shirley & Marty: An Unlikely Love Story, in 1990. Jones survives him.