The film was made and released about three years after its source play of the same name by Neil Simon was first performed in 1968. The original Broadway production of the play opened at the Plymouth Theater on 14th February 1968 and ran for 1097 performances until 3rd October 1970. The play was nominated for three 1968 Tony Awards including Best Play and Best Actress - Maureen Stapleton. The Broadway stage production was directed by Mike Nichols who won the Tony for Best Director. Stapleton and Jose Ocasio reprise their roles in this movie version.
Maureen Stapleton recreated ONE of her three roles from the stage version. Like the male roles, Neil Simon wrote all three female roles to be played by one actress. George C. Scott and Maureen Stapleton originate all of the roles in the play; Walter Matthau took over for Scott in all three roles - Stapleton kept her role from the first act; the other two roles went to Lee Grant and Barbara Harris.
Neil Simon's "Plaza Suite" play's description in the play is described as being comprised of three one acts, the title for each is: "A Visitor from Mamaroneck"; "A Visitor From Hollywood"; and "A Visitor From Forest Hills". The movie is chaptered the same way. It's setting in the play is described as being "A suite in the Plaza Hotel. A Late Winter afternoon, Early Afternoon in Spring, and a Saturday afternoon in June."
The "Plaza Suite" play by Neil Simon originally had four acts instead of three. One of the acts of was cut during pre-production of the play, Simon later re-worked and expanded it for the film The Out of Towners (1970). It was entitled "Visitor from Toledo" and was intended to open the play on Broadway but was cut during the rehearsal period. Simon once described the one-act to the 'Newark Eveing News' as being "...about a man who came to New York from out of town and lost his luggage. He got there in the middle of a transit strike. It was snowing. So after he had checked into the Plaza [Hotel] he had this monologue. We put 'Plaza Suite' into rehearsal, and after about the fifth day [the director] 'Mike Nichols' said 'We just have too much show here. If we include that monologue, the curtain will be coming down at midnight'".
Walter Matthau plays three characters in this film: Sam Nash, Jesse Kiplinger and Roy Hubley. Matthau plays all three lead male roles in all three segments. In the remake, Plaza Suite (1987), actress Carol Burnett played all three lead female parts in all three stories.
This film's screenwriter and source playwright Neil Simon once said of this movie: "I didn't like the cast. I didn't like the picture. I would only have used Walter in the last sequence and probably Lee Grant. I think Walter Matthau was wrong to play all three parts. That's a trick Peter Sellers can do. I have to accept some of the blame for the film. I kept all the action in one room. It was rather confining. We could have gone into other suites. I didn't think it out, but I learned from that."