Harley Quinn is real-life best friends with her Yoga Hosers (2016) co-star, Lily-Rose Depp. The two met in Kindergarten at the Hollywood Schoolhouse.
Plays bass guitar.
Harley Quinn is named after the Batman character. Her father, Kevin Smith, is a self-proclaimed fanatic and even runs a podcast called "Fat Man on Batman".
Plays bass for the bubblegum pop band The Tenth. They have an EP "Boys We Don't Know" and their debut album "Dunes" which came out in 2019. In addition to playing bass, Smith also sings.
Harley is a Disney lover. She frequents goes to Disneyland often in her home state of California.