- Celebrity Voice Actor: Like all Ghibli films since Princess Mononoke, the Japanese version features actress/model/singer Sara Takatsuki as Anna, actress Kasumi Arimura as Marnie, actress Hana Sugisaki as Sayaka, singer/actor/director Hitomi Kuroki as Hisako, actress Nanako Matsushima as Yoriko Sasaki, and singer/actress Ryoko Moriyama as the elderly Marnie.
- Promoted Fangirl: American musician Priscilla Ahn originally composed "Fine on the Outside" on 2005 after feeling herself, when she was younger, friendless and alone, which made her turn to music. Given the personal subject of the song, she never released it. However, when Ahn, a big fan of Ghibli, found out the studio was going to adapt the Joan G. Robinson novel, she decided to read it and, seeing much of herself in Anna, decided to submit the song to Ghibli. Later Yoshiaki Nishimura, the film's producer, contacted her telling her how much he loved the song. It was eventually chosen as the official theme of the movie. She also released Just Know That I Love You, an official companion album of sorts - the album cover is an image of Marnie taken from the film, and while only "Fine on the Outside" was included in the film itself, the rest of the songs were inspired by the movie's plot and themes.
- Swan Song: This was longtime Ghibli animator Makiko Futaki's last film before her death four years after the film's release.
Trivia / When Marnie Was There