One Day At A Time's Mackenzie Phillips Couldn't Stand This Co-Star

"One Day at a Time" alum Mackenzie Phillips has a complicated history and relationship with the show that made her a star. Although she appeared as central character Julie Cooper in the majority of the classic sitcom's episodes, Phillips was actually fired from "One Day at a Time" not once, but twice — with both dismissals stemming from her well-documented struggles with substance abuse. Mind you, Phillips has no hard feelings about being let go. "[T]hank God I got caught, you know?" she told Fox News Digital in May 2026. That being said, Phillips' personal tragedies were far from the only source of drama on-set. By her own admission, she absolutely couldn't stand one of her co-stars.

During an appearance on former "One Day at a Time" co-lead Valerie Bertinelli's "Getting Naked" podcast in September 2026, Phillips briefly spoke about the antagonistic relationship she once had with their fellow co-star Richard Masur, who played David Kane on the show. "One person — and I have made peace with this person, and we've spoken — but Richard Masur wasn't very nice...He wasn't very nice," Phillips said. Bertinelli was quick to point out, Masur wasn't actually part of "One Day at a Time" for long. He appeared in every episode of Season 1, which was notably the shortest season of the show, before departing a few episodes into Season 2. Nevertheless, Phillips stood by her statement.

Interestingly, Masur returned to "One Day at a Time" for a guest spot in Season 6. Coincidentally, that just so happens to be the only season Phillips missed entirely following her first firing.

During her aforementioned appearance on Valerie Bertinelli's "Getting Naked" podcast in September 2026, Mackenzie Phillips also went into a little bit of detail regarding how exactly she eventually "made peace" with former "One Day at a Time" co-star Richard Masur. "I saw him, and he said, 'I don't even remember what it was, I don't even remember what I said, but whatever I said, I'm really sorry. And I've always thought you were so incredibly talented, and we were all so young.' And, you know, that kind of thing," Phillips recalled.

Notably, Phillips and Masur have publicly reunited on a number of occasions in the years since their apparently tense time working on "One Day at a Time" together came to an end. The actors shared the stage as part of a larger cast reunion that took place at the 10th Annual TV Land Awards back in 2012. At that event, the show's cast members — who look quite a bit different than they did back in the '70s and '80s — also filmed special reunion material for "Good Morning America."

As for Masur himself, the actor has made it clear how much he loved working on "One Day at a Time." During a February 2016 interview with The A.V. Club, however, he also confessed that he was more than happy to leave the show after a season and a half, and had no regrets about doing so. "Listen, I am so grateful for 'One Day at a Time,' even though for years and years and years people would go, 'Oh, you were on One Day at a Time,'" Masur said, likening his brief time on the show to a specter that has continually followed him.