Gregoire was one of the leaders for the animatics team that worked on Star Wars: Attack of the Clones.

Animatics are animated, digital storyboards that pre-visualize what scenes will look like, and allow the director to add, subtract, or change scenes in a cost-effective way, often before the actual shooting for the film begins. Not only do directors make use of animatics, but the actors, film editors, effects artists, and others do as well.

Gregoire started out at Mankato State University in Minnesota pursuing aviation and business studies, but soon realized his true passion lay with art. He began working in digital art, and designed his own curriculum and major in the school's open studies program. After graduating with a Bachelor of Science degree from Mankato, and an associate's degree in animation from a school in Minneapolis, Gregoire went to work as a graphic designer.

From there, Gregoire moved to San Diego, to work for Presto Studios. He was introduced to David Dozoretz, who invited him to join Persistence of Vision Digital Entertainment (POVDE). While at POVDE Gregoire worked on Titan AE, Moulin Rouge, and Behind Enemy Lines.

Gregoire joined David Dozoretz, who had worked on Episode I, on the pre-visualization team for Episode II Attack of the Clones. At the start of production, Gregoire was a production artist with some assistant managerial responsibilities. He eventually advanced to manager of the pre-visualization department, and was a leader for the animatics team.

Gregoire and his team provided more than 4000 animatic sequences for Attack of the Clones.