Mary Catherine Garrison was born in Clarksdale, Mississippi and raised in New Orleans, Louisiana. Her acting training began in high school at New Orleans Center for Creative Arts (NOCCA). She then received her BFA in acting at University of Evansville. She then received her MFA in acting at University of California, San Diego (UCSD) in 1999. Her Broadway debut was in 'The Man Who Came to Dinner' with Nathan Lane. She is also known for her sprightly and bubbly personality. She resides in New York City.