Richard Mulligan was originally considered for the role of Chester Tate, but director Jay Sandrich felt he was better suited to play Burt Campbell instead, and suggested Robert Mandan (whom he had directed on The Mary Tyler Moore Show) for Chester Tate.

Casting the role of Benson proved very difficult, with the production reading women, Asian, Black, and Norwegian actors before realizing they were essentially looking for Robert Guillaume, whom Sandrich remembered as a dynamic performer despite never having seen him do comedy.

The actress originally cast as Mary Campbell in the initial pilot was replaced because she was deemed 'just as neurotic' as Richard Mulligan's character; network executive Fred Silverman authorized reshooting the pilot with Cathryn Damon instead.

Rod Roddy became the show's off-camera announcer after original announcer Casey Kasem quit following the pilot episode.

Before it even aired, Soap sparked massive controversy after a Newsweek preview by Harry F. Waters mischaracterized its content (falsely claiming a priest was seduced in a confessional), prompting religious organizations like the National Council of Churches and the Catholic Church to call for boycotts, and leading ABC to lose sponsors and have 18 of its 195 affiliates refuse to air the premiere.

ABC's internal Standards & Practices department issued a lengthy 'Soap Memo' restricting language and storylines (such as banning the word 'transsexual' and removing a subplot involving a Vietnamese opium smuggler); the memo was leaked and published in full by the Los Angeles Times in June 1977.

One note in the leaked censor memo asked that a scene with Claire dumping hot coffee on Chester be redirected away from his crotch; creator Susan Harris later said the producers ignored the note and poured it in his lap anyway.

British actress and comedian Catherine Tate chose her stage surname 'Tate' in honor of the character Jessica Tate from Soap.