Chun was a staff writer for the ABC television series Once Upon a Time (TV series). He wrote, alongside of Scott Nimerfro, episodes 11 Shattered Sight and 17 Heart of Gold (Once Upon a Time) of the Fourth Season, and Episodes 6 The Bear and the Bow (with Andrew Chambliss), 10 Broken Heart (Once Upon a Time) and 16 Our Decay (both with Diana Hogan) for Season Five.
