Philip McKeon, a former child actor best known for playing the son on the CBS sitcom “Alice,” died on Tuesday morning in a hospital in Texas. He was 55.

A family spokesman, Jeff Ballard, said he died after a long illness, which he declined to specify.

From 1976 to 1985, Mr. McKeon, the older brother of the actress Nancy McKeon, played Tommy Hyatt on “Alice.” The show, loosely based on the movie “Alice Doesn’t Live Here Anymore,” starred Linda Lavin as a widow and aspiring singer who works as a waitress at a roadside diner in Phoenix. Viewers watched Mr. McKeon grow up on the show as he played the smart and loving preteen son with a toothy grin who went on to play basketball in college. He appeared in more than half of the show’s 202 episodes.

The show’s cast also included Vic Tayback as the diner’s owner and Polly Holliday, Beth Howland, Diane Ladd and Celia Weston as waitresses.