Calista Kay Flockhart was born in Freeport, Illinois, to Kay and Ronald Flockhart. Her father was a Kraft Foods executive, leading the family to relocate several times during her childhood. This early exposure to new environments and people likely contributed to her adaptability and openness, qualities that would later serve her well in her acting career. The frequent moves instilled a sense of resilience and independence in her from a young age.

After graduating with a Bachelor of Fine Arts degree in theater from Rutgers University, Flockhart began her professional acting career on stage. She made her off-Broadway debut in 'Beside Herself,' gaining valuable experience and honing her skills. These early stage roles were instrumental in building her confidence and mastering the craft of acting. They demonstrated her dedication to the art form and her willingness to put in the hard work necessary to succeed.