After working as a child actor in the United Kingdom, Marcel had her breakout as a screenwriter in Hollywood when her script for Saving Mr. Banks made the 2011 Black List and was quickly acquired by Disney, which released the film in 2013.
Marcel also created and served as executive producer of the television series Terra Nova (2011) and The Changeling (2023), for which she was also the showrunner and is credited with writing eight episodes.
Marcel worked as a child actor in the United Kingdom, playing minor roles in television series such as The Bill, Holby City, and Casualty.
Gondwanaland Highway was almost picked up by Carnival Films, the UK production company behind Downton Abbey, when producer Aaron Kaplan persuaded Marcel to bring the show to America instead.
[4] After her two-week trip to Los Angeles and her decision not to continue working on Terra Nova, Marcel returned to the London video shop.
[6] The film was released in 2013, directed by John Lee Hancock, and starring Tom Hanks as Walt Disney and Emma Thompson as P. L. Travers.
Marcel worked in close, intense collaboration with author Victor LaValle in adapting his award-winning 2017 novel The Changeling into a television show with the same name for Apple TV+ that premiered in October 2023.
"[17] The show was well received by critics, with Allison Picurro of TV Guide writing that "Anyone willing to go along for the ride is in for an enchanting storybook of a series, one of the year's most singular offerings."