Park was born near the Iguassu Falls in Foz do Iguaçu, Paraná, Brazil to Korean parents who ran a business in Brazil. At the age of 8, she moved with her father and siblings to Southern California and spent the remainder of her childhood there. She grew up in Torrance, California and attended Torrance High School. She states she has only been to Korea on vacation.
In June 2008 Park became a United States citizen. She also retains her Brazilian citizenship.
Park was successful in the American Junior Golf Association, winning five times. In 29 events in four seasons, she posted 24 top-10 finishes. In 2005, she reached the semifinals of the USGA Women’s Amateur Championship, the premier amateur tournament for women golfers in the world.