Lurch is the household butler. Morticia and Gomez summon him by means of a bell pull in the form of a hangman's noose, which rings the massive bell located in the mansion's bell tower (the resulting gong shakes the entire house when the noose is pulled). When Lurch appears (usually immediately thereafter), he responds in a very deep bass voice, "You rang?" According to IMDb, Lurch was intended to be a non-speaking part, as the Charles Addams cartoon character was silent. However, Cassidy improvised the line during his audition, and it was well received and incorporated into the show. When questions are posed to Lurch his primary response is a deep annoyed grunt, from which the family glean complex meanings.

He is superhumanly strong and often plays the harpsichord (the music is actually played by The Addams Family composer Vic Mizzy) which had previously been owned by Cousin Crimp. Lurch is very high-minded about visitors. When an undercover operative named Mr. Hollister (played by George Neise) visited the family, Lurch patted him down and regarded him suspiciously when he found his gun. Mr. Hollister showed Lurch his badge, whereupon Lurch returned the gun. Also, when announcing the arrival of visitors in the foyer of the Addams' home, the towering servant invariably grabs and crushes any hats being worn by male guests.

Lurch at times regards his employers' activities with some dubiousness much like a servant expressing disdain for the idle rich; and on those occasions when he feels overworked or stressed, he, like Uncle Fester, seeks therapeutic relief by being stretched on the family's torture rack. Ted Cassidy made a cameo appearance as Lurch on an episode of the Batman TV series.