The film began production in 1948 under the title "La Bergère et le Ramoneur". However, due to production and budgetary issues, the film's producer, André Sarrut, chose to release the film unfinished in 1952, much to the dismay of Paul Grimault. Fifteen years later, Grimault regained the rights to the film and spent the next decade gaining financing and gathering original animators to finish the film as was originally intended. The film was released in 1980, thirty-two years after production began. As of 2024, the film is the current record holder for longest production time of a completed animated film.
The King's tower would be used as an inspiration for Hayao Miyazaki's Lupin III: The Castle of Cagliostro (1979); Gorô Naya, the voice of Kouichi Zenigata, would voice the King and his portrait double when 'The King and the Mockingbird' was dubbed into Japanese.