The film won several awards, including a diploma speciale from the 1957 Venice Film Festival and the Grand Prize at the 1958 Montevideo Film Festival. In 1957, Hubley was also hired by the advertising firm Fletcher, Richards, Calkins & Holden to direct the hugely successful “I Want My Maypo!” commercial. For the first time in his career, Hubley used the voice of one of his children, his stepson Mark, for the commercial. The commercial led to a boom of sales for Maypo, and the character of “Marky Maypo” (named after his stepson) became the cereal’s mascot. The commercial is also credited for beginning the trend of using animation to sell products to children, as it “exploit[ed] children's less than fully developed ability to distinguish between entertainment and selling”. Around this time, Hubley met musician Dizzy Gillespie through mutual friend Paul Robeson, and the Hubleys soon made their first film with Gillespie, A Date with Dizzy (1956). The film contained many of the advertisements Hubley had already made at Storyboard, Inc., as well as an original segment by a then-unknown R.O. Blechman. Following the success of the Maypo spot, John and Faith turned their attention to producing more short films. Their next film, Harlem Wednesday (1957), marked the first time John and Faith were credited alongside one another on-screen (though Faith is credited as Faith Elliott). The film, an experimental montage of paintings by Gregorio Prestopino with a score by Carter, further explored the Hubleys’ desires to push animation towards modern art. Their next film, Tender Game (1958), included an unused track by Fitzgerald from Finian’s Rainbow. Hubley experimented with multiple exposure effects on the film to give it a distinct look and dimensionality. Mark Hubley would later remark “the film has always struck me…as a love letter between [John and Faith], the figures…look like mom and dad”. The film won the grand prize at both the Venice Film Festival and the Montevideo Film Festival. Hubley was inspired by his earlier work on the Mr. Magoo films with Jim Bauckus to experiment with films centered around improvised dialogue, as he often encouraged Baukus to riff in the studio. In 1958, Hubley recorded his sons Mark (aged 6) and Ray (aged 3) his sons playing a game where they search for a “Moonbird”, referring to a pet bird the family had lost recently by leaving a window open. Faith edited the conversations