Dr. Mitsui was born in Tokyo Japan. She grew up in Tokyo, Chicago and New York. Dr. Mitsui graduated from Cornell University College of Medicine and completed an internship at the Animal Medical Center in New York. After a surgical internship at Sonora Veterinary Specialists, Dr. Mitsui completed her combined surgical residency with North Carolina State University, University of Florida, and Sonora Veterinary Specialists.

She enjoys backpacking, swimming, traveling and dining out for leisure.