She grew up in New Jersey. She attended Pratt Institute, graduating in 1969 with a BFA in commercial art. She started her career at Holt, Rinehart, and Winston, designing their first basic reading series, K-8. Since 1972, Ms. deGroat has free-lanced in advertising, editorial, and design, but the main focus of her work has been in children's book illustration, with over 100 books so far. Many titles are for well-known authors such as Eve Bunting, Lois Lowry, Johanna Hurwitz, and even Dr. Ruth. Her most recent challenge has been writing and illustrating her own stories.
Her best-selling picture books include: Trick or Treat, Smell My Feet, and Roses are Pink, Your Feet Really Stink, an IRA-CBC Children's Choice and State Children's Book Award winner in Arkansas and North Carolina. She wrote and illustrated 19 books in the Gilbert and Friends series and her Charlie the Ranch Dog was a New York Times bestseller