Joy Cretton is a costume designer. Cretton was born in Haiku, on the island of Maui, Hawaii. Growing up in a creative, close-knit family of six children, she and her siblings were homeschooled by their mother, who encouraged imaginative exploration. Joy later moved to California with her family to pursue her passion for design and the arts.

Her career in costume design has spanned both independent films and blockbuster productions. She is credited for her work on acclaimed films like Short Term 12 (2013) and Just Mercy (2019), and gained wider recognition as an assistant costume designer for Marvel's Shang‑Chi and the Legend of the Ten Rings (2021). She served as costume designer on Disney+'s American Born Chinese (2023), the live‑action adaptation of Gene Luen Yang's National Book Award–nominated graphic novel. In American Born Chinese, Cretton led a visually striking and culturally sensitive costume narrative that blended traditional mythological aesthetics with contemporary fashion. She collaborated with Asian‑American designers like Prabal Gurung, Phillip Lim, Kenneth Barlis, and Vivian Chan. She incorporated runway and ready‑to‑wear pieces alongside bespoke creations. Notable designs include Michelle Yeoh as Guanyin, featuring jade and lotus motifs, Ke Huy Quan's Guan Yu battle‑ready robes, Poppy Liu's Princess Iron Fan profile, and Jimmy O. Yang's Dragon King suit. Cretton's work was widely praised for channelling the series' emotional arcs, mythic grandeur, and cultural authenticity. Joy has also collaborated closely with her brother, director Destin Daniel Cretton, who has described her as an essential creative partner. She returned to the Marvel Cinematic Universe to serve as costume designer for her brother's Disney+ TV show, Wonder Man (2025).