As with all Ghibli films since 1997, quite a few famous Japanese actors and comedians provide several roles in the film, such as Tomoko Yamaguchi, George Tokoro, Kazushige Nagashima, Yuki Amami, Tomoko Naraoka, and Kazuko Yoshiyuki. Rumi Hiiragi, who voiced Chihiro in Spirited Away, voices the young mother.
Promoted Fanboy: Fujimoto's English VA Liam Neeson was familiar with Miyazaki's works before he was cast.
Reality Subtext: Miyazaki made Ponyo as a means of trying to reconcile with his estranged son Goro (the one who directed Tales from Earthsea). Throughout the film, Sosuke and his father are separated.
Real-Life Relative: Joe Hisaishi's daughter Mai sings vocals on several cues of the film's score. Mai even sang the image song "Rondo of the House of Sunflowers".
The English dub's executive producer, Kathleen Kennedy, is the current leader of Lucasfilm (which also produced the English dub through Skywalker Sound) and the producer of the newer Star Wars films and shows.
So My Kids Can Watch: For the English dub, Megan Marshall, the daughter of the English version's executive producers Frank Marshall and Kathleen Kennedy, suggested that Frankie Jonas and Noah Cyrus should play Sosuke and Ponyo, respectively.
Studio Hop: Ponyo is the first Studio Ghibli film to have its English dub recorded at Skywalker Sound instead of Buena Vista Sound Services, which was re-branded as Disney Digital Studio Services Sound Department in 2009.
According to Miyazaki, Ponyo was originally a tin wind-up toy frog. Because of the strange concept, he changed her to a fish who shifts into an amphibian creature at times.