Hiraoka was born in Yokohama. She was inspired by Broadway musicaks when she went to study dance in New York and began a career in acting. She appeared in films such as Go Riju's Wharf, Midnight and Sion Sono's Tag. She moved to the U.S. in 2017, and returned to Japan after studying in New York for a year and a half. Since then, she has continued her acting career while also being involved in directing and script-writing her own films.