Not long sfter she moved to Honolulu, Hawaii, Hirono attended Koko Head Elementary School. Once she had graduated from Kaimuki High School with honors in 1966, Hirono continued her education by enrolling at the University of Hawai'i at Manoa. There, Hirono earned a B.A. in Psychology and graduated as a Phi Beta Kappa in 1970. This made Hirono the first person in her family to graduate college.
Determined to educate herself as much as possible, Hirono attended Georgetown University Law Center in Washington D.C. While she was there, she focussed on studding public interest law. When she graduated as a JD (Juris Doctor) in 1978, she returned to Honolulu, Hawai'i and started her own private practice as a Deputy Attorney General. In 1987, Hirono married Leighton Kim Oshima. She now has a step-daughter named Malia. Hirono follows the Buddhist religion.