Dr. Marilena Constantinou grew up in the Central Valley of California. She acquired a Bachelor of Science from UC Berkeley. After her undergraduate degree, she worked as a veterinary assistant for two years in San Francisco before earning her DVM from Western University of Health Sciences College of Veterinary Medicine.

During her last year of veterinary school, Dr. Constantinou developed a strong interest in small animal emergency medicine as well as feline medicine. She went on to complete a small animal rotating internship at VCA West Los Angeles Animal Hospital. Her hobbies include roller-skating, vintage shopping, and cooking Greek cuisine. She has one cat at home that she acquired during her time in vet school. Dr. Constantinou is fluent in Greek.