In an interview on the NPR program "Fresh Air", Julianne Moore said that she drew on Courtney Love and Patti Smith for inspiration for her character in this movie, who is (like Love and Smith) a rock star who is also a mother.
Working with 6-year-old actress Onata Aprile meant that the crew had to do most of the filming before her bedtime. However, during a scene that had to be filmed at night, Aprile fell asleep, and could not be woken up. The scene had to be shot two weeks later.
Casting for the role of Maisie took eight weeks. Casting director Avy Kaufman suggested about 100 young girls to McGehee and Siegel while the directors independently visited New York elementary schools to hold auditions. Six-year-old Onata Aprile auditioned relatively late, and was cast three weeks before production started.
The ending in the film is different from the novel. In the novel's ending, the final scene takes place in Paris and Maisie has difficulty choosing to stay with her step parents and her guardian Mrs. Wix. Eventually she concludes that her new parents' relationship will likely end as her biological parents' did. She leaves them and goes to stay with Mrs. Wix, her most reliable adult guardian. The film is set in present-day New York City, and the professions of Maisie's parents are changed. Unlike in the book, Maisie's step parents are highly dependable and love her and each other deeply. Maisie finds a happy life with them, and the character of Mrs. Wix is virtually eliminated.