One Day at a Time is a Partridge Family song.
In real life[]
The song was written by Terry Cashman and Tommy West. It can be found on Crossword Puzzle.
On the series[]
In A Likely Candidate, the Partridge Family is shown playing the end of the song on the bandshell at the park during Richard Lawrence's campaign rally. Keith Partridge doesn't play an instrument.
In Aspirin at Seven, Dinner at Eight, the Partridge Family plays the entire song at a nightclub in front of a wall of stained glass. Bernie Applebaum and Mrs. Applebaum are in the audience. After the performance, Bernie visits the Partridges in their dressing room to break up with Shirley Partridge.