Jerry Lewis (as Christopher Pride) wants to marry Janet Leigh (as Elizabeth "Liz" Acord) and move to Paris, where he has been commissioned to design a mural. But, Psychiatrist Leigh doesn't want to leave her patients; especially three strikingly beautiful women, who can't seem to develop romantic relationships with men. Mr. Lewis decides to assume three different alternate identities, in order to warm up the three frigid women, and free up fiancée Leigh. Will things get too hot?
Leigh and the three women (Mary Ann Mobley, Leslie Parrish, and Gila Golan) are lovely looking; but, don't watch for them to run around in bikinis and towels a lot -- there isn't much skin on display. James Best (as Ben Mizer) handles the role of Lewis' straight man well. The supporting cast performs ably; Kathleen Freeman and Buddy Lester are always fun to watch, drunk or sober. Lewis plays his "main" personality and four others -- "Warren", "Ringo" (not Beatle-influenced), "Rutherford", and "Heather". They are not complicated characterizations and, so, are not among is best.
"Three on a Couch" is interesting in its overindulgence. It's the Lewis brand, with a drink in one hand, and a cigarette in the other. Note, the script and situations are drenched in alcohol. This gives the film a "drunk", enochlophobic feel. The film's closing "party" has a surreal quality, with guests pouring into spaces they shouldn't fit. Lewis directs this "party" scene very effectively, by the way; his directorial skill is sometimes overshadowed by his on screen persona -- he might have been wise to peruse a parallel career directing movies in which he does not appear.