Hui was born in Hong Kong, and grew up in a single parent family, with his mother raising him and two other siblings. Liking to draw since he could remember, he went to Hong Kong Polytechnic University where he graduated in 1984 in graphic design.
After the graduation, he worked as a cel Animator at Quantum Studios in Hong Kong. In 1989, he moved to Canada to attend a three-month course at Sheridan College to improve his knowledge in computer animation. For a while he was creating hand-drawn animated productions for TV commercials in Toronto. In 1989, Hui started working as a junior Animator at Pacific Data Images, which was later acquired by DreamWorks Animation. There, he worked on various commercials and short films. Among other work, he directed two short films, Sleepy Guy (1995), and Fat Cat on a Diet (2000). He was the supervising Animator and lead character designer on PDI's first feature film, Antz, released in 1998. From there he went on to serve as supervising Animator for Shrek and Shrek 2. In 2004, he spent half a year in Hong Kong where he directed animation for the DreamWorks Animation's televisions series Father of the Pride, which was subcontracted to a Hong Kong company. In 2007, he co-directed his first feature film, Shrek the Third. He also directed three short films, Kung Fu Panda: Secrets of the Furious Five, Scared Shrekless and Puss in Boots: The Three Diablos.
Hui illustrated several children story books in collaboration with Kiehl's to raise funds for various Hong Kong organizations. His first book, Brownie and Sesame was released in 2004, followed by Piccolo in 2005 and Grandma Long Ears in 2006.
Due to his contributions to the Shrek films, Forbes listed Hui in 2010 among 25 notable Chinese-Americans in the Business field.