Pat Harrington Jr., best known for his role as the seedy super on “One Day at a Time,” died Wednesday night in Los Angeles. He was 86.

His daughter, Tresa Harrington, announced the news Thursday on her Facebook page. She did not reveal the cause of death, but wrote in November that her father’s health was rapidly deteriorating after being diagnosed with Alzheimer’s disease.

“My heart is broken to pieces and I will cry and cry until I just won’t,” she said in the post.

Harrington won a Golden Globe (in 1981) and an Emmy (in 1984) for playing building superintendent Dwayne Schneider on the groundbreaking CBS sitcom, which aired from 1975 to 1984. The show starred Bonnie Franklin as an single mom struggling to raise two daughters (played by Mackenzie Phillips and Valerie Bertinelli).

“He turned out to be the comic strength of the show,” show co-creator Norman Lear once said.

Harrington sold ads for NBC after a stint in the Air Force during the Korean War and before his big break as an actor.

Schneider also appeared on “The Steve Allen Show,” “The Danny Thomas Show” and “Owen Marshall, Counselor at Law,” in addition to doing voice-over work for cartoons.

Harrington had small roles in films such as Elvis Presley’s “Easy Come, Easy Go” (1967), James Coburn’s “The President’s Analyst” (1967), Terry-Thomas’ “2000 Years Later” (1969) and Robert Redford’s “The Candidate” (1972).

In recent years, he made guest appearances on TV shows such as “Curb Your Enthusiasm” and “Hot in Cleveland,” reuniting with Bertinelli.