The role of Sheila Shea was originally written for Sandy Dennis. Co-star Paul Dooley was seriously allergic to cats though. When cat-lover Dennis would come to the script readings with up to five cats at a time, he was briefly hospitalized. The role was then offered to Shelley Duvall, who had worked with director Robert Altman on six pictures, but she turned it down. As a result, Allan F. Nicholls then re-wrote the role of Sheila Shea from an earth mother type to the young singer-groupie played by Marta Heflin. Both stars had appeared in the director's previous film A Wedding (1978) which had premiered the previous year in 1978. Duvall and Altman would collaborate on a motion picture one more time the following year with Popeye (1980).
Actor Paul Dooley did not find out he had been cast in the film until a friend told him that it was mentioned in show-business trade-paper "Daily Variety".
According to 'DVD Talk', "[Director Robert] Altman purposely kept 'A Perfect Couple' a little ragged [i.e. low-budget and without big names]. He wanted his lead actors to be more like normal people than big movie stars".
The name of the band was ''Keepin' 'Em Off the Streets".