But younger audiences knew him too - for a slew of recent parts such as the doctor on the 2008 hit movie "Forgetting Sarah Marshall."
The veteran actor died Monday at age 65, his agent, Jeffrey Leavitt, told The Associated Press. The cause of death wasn't released.
Landesberg appeared in dozens of TV shows, his curly haired, bespectacled face easily recognizable. Recent credits included "Everybody Hates Chris," "Just Jordan," "That 70s Show" and "American Dad."
"He was a wonderful comic and superb actor who gave so much of himself in every performance," said Shirley Jones, who appeared opposite Landesberg in what was one of his final appearances, an episode of "The Cleaner" last year.
His most successful role was that of Dietrich on "Barney Miller, which was set in a New York City police station populated by oddballs and eccentrics. It aired from 1975 to 1982.
Landesberg's Dietrich was noted for his endless knowledge and expertise on seemingly every obscure subject imaginable, which was coupled with a sometimes patronizing attitude. He once refused to wish a Happy Thanksgiving to a fellow officer, explaining he was an agnostic and wouldn't know who to thank.
In "Forgetting Sarah Marshall," he listened patiently as Marshall's former boyfriend described a sexual tryst, then revealed he was really a pediatrician.
Landesberg also played a doctor in the TV series "Head Case," which aired from 2007 to 2009.
Other TV credits included "The Rockford Files," "Two Guys, a Girl and a Pizza Place," "Cosby," "Law and Order" and "The Golden Girls."
Information on survivors was not immediately available.