Ross Hunter wrote that after he made this film, no theatre managers wanted to book it. Popular movie themes at the time were war films, westerns, or spectacles. Hunter was told by the big movie chains that sophisticated comedies like "Pillow Talk" went out with William Powell. They also believed Doris Day and Rock Hudson were things of the past and had been overtaken by newer stars. Hunter persuaded Sol Schwartz, who owned the Palace Theatre in New York, to book the film for a two-week run, and it was a smash hit. The public had been starved for romantic comedy, and theatre owners who had previously turned down Ross Hunter now had to deal with him on HIS terms.
Towards the end of the movie Rock Hudson picks up Doris Day and carries her through the lobby and down the street. After many takes, Hudson's arms were hurting, so they created a sort of sling which held Day in a crate-like device and hooked over Hudson's shoulders to evenly distribute her weight.
At the diner, after Jonathan (Tony Randall) slaps Jan (Doris Day) a truck driver, John Indrisano, punches him in the jaw. In an interview, Randall said that he and Indrisano practised the punch many times and Indrisano assured him that he would not be hit. During the take Indrisano misjudged and Randall was actually struck and knocked unconscious.
Spanish TV screened "Pillow Talk" on 20th July 1969 while everybody was waiting for the Apollo landing on the Moon. Suddenly, the film stopped and Spanish people could see the landing live. The film was not reshown on TV until 1999, when Spanish viewers could, at last, see the ending!
Despite being contractually bound by Universal to do the film, Rock Hudson consistently declined it, fearing it was too dirty and would harm his masculine image. Doris Day finally talked him into starring in it, and subsequently it became one of his biggest hits.
According to Universal Studios, Tony Randall was supposed to fake a reaction to being decked in the face by one of the restaurant patrons. However, during filming, the actor overestimated and actually knocked out Randall. The shot was so well done, it was used in the film.