Her screenwriting debut, Foodfight!, was released in 2012. She wrote the script for the fourth BIONICLE movie The Legend Reborn. Derek was also the writer for the first Zhu Zhu Pets straight-to-DVD film Quest for Zhu.
Derek worked at Hanna Barbera Productions for shows like The Smurfs and Captain Planet, she was also a story Editor for both shows. Derek was also a story editor/writer of Batman: The Animated Series. But many Batman scripts she worked on weren't approved by Standards and Practices. Episode P.O.V was one of them.
Here are some of the Smurfs shorts and episodes Sean Catherine Derek worked on.