Joyce began his film career as a concept artist for Toy Story (1995), and has since been active in both animation and live-action.

[4] Joyce has written and illustrated over 50 children's books including George Shrinks, Santa Calls, Dinosaur Bob and His Adventures with the Family Lazardo, Rolie Polie Olie, The Leaf Men and the Brave Good Bugs, A Day with Wilbur Robinson, The Fantastic Flying Books of Mr. Morris Lessmore, The Guardians of Childhood series, and many others.

With his company Moonbot Studios, Joyce along with his partners, produced the Lessmore story in a variety of media and mediums simultaneously.

A short film was in production (using handmade miniature sets) while the book was being illustrated (along with Joe Bluhm) and an interactive story app was being devised.

[6] In 2005, Joyce and Reel FX launched a joint venture, Aimesworth Amusements, to produce feature films, video games and books.

[7] The new company announced plans to make three feature films:[8] The Guardians of Childhood, The Mischevians, and Dinosaur Bob and His Adventures with the Family Lazardo.

[10] Joyce was originally slated to direct the film, however early in the production his daughter Mary Katherine, his wife Elizabeth, and his sister Cecile were diagnosed with terminal illnesses.

[11] The studio produced an Oscar-winning animated short film[12] and an iPad app[13] The Fantastic Flying Books of Mr. Morris Lessmore.

[15] In 2013, Blue Sky Studios adapted Joyce's book The Leaf Men and the Brave Good Bugs into the film Epic, with him serving as writer, executive producer, and production designer.

DNEG also announced they would be producing a feature animated film adaptation of The Great Gatsby, directed by Joyce and written by Brian Selznick.

On February 26, 2012, he won an Academy Award for Best Animated Short Film, The Fantastic Flying Books of Mr. Morris Lessmore.

[20] The main character of Epic, which is based on Joyce's book The Leaf Men and the Brave Good Bugs, was named after her.

[21] His wife, attorney Frances Elizabeth Baucum Joyce, died on January 20, 2016, at the age of 55, due to complications of ALS.

He sold prints of his unpublished Mardi Gras The New Yorker cover, with profits going to Louisiana artists and arts organizations.