O'Brian was born on February 12, 1989, in Indianapolis, Indiana, and has three older brothers. She is of mixed ethnicity, with African-American and European-American ancestry.[3] O'Brian began studying martial arts at five years old, and at age nine earned her brown belt in Shorei Goju Ryu Karate.[4] Throughout her youth, she participated in numerous sports programs and also in music programs as a percussionist.[5]
She attended Indiana University Bloomington, majoring in psychology and Germanic studies.[6] She was one of the first members of the university's short-form improv troupe Hoosonfirst. She received law enforcement certification through the university's Cadet Officer Program. At university, she received her black belt in hapkido through the US Hapkido Federation.[7]
After graduation, she was a police officer for seven years at the Carmel Police Department in Carmel, Indiana, including the department's Crisis Intervention Team, which specialized in helping individuals with various conditions such as psychosis, depression, Alzheimer's, and autism.[8] She obtained her personal trainer certification and began competing in bodybuildingfigure competitions,[9] and began training at the Indy Actors Academy.[10] She competed twice in figure, in September 2014 and May 2015, but stopped because of the expense and because she did not want to take steroids like some other competitors.[11]
In 2016, O'Brian moved to Los Angeles to pursue a career in film and television. While waiting to land a role, she worked with the University of California, Los Angeles Martial Arts Program, helping with self-defense classes and instructing the Hapkido program. Through the same program she also studied Muay Thai and Brazilian Jiu Jitsu.[8]
In 2018, O'Brian booked her first regular role on the comedy action series Z Nation where she played George, a budding leader of the apocalypse. In 2019, she appeared in the CW series Black Lightning as an ASA antagonist, Major Sara Grey. She appeared in season 3 of HBO's Westworld.
In 2020, O'Brian was cast as Elia Kane, a key recurring character in Seasons 2 and 3 of the Star Wars series The Mandalorian.[13]
In 2022, it was announced that O'Brian would star opposite Kristen Stewart in Love Lies Bleeding, her first major film role.[15] The film was released theatrically by A24 on March 8, 2024.[16]
Personal life
Shortly after moving to Los Angeles in 2016, O'Brian met her partner, Kylie Chi, on a student film project set. The couple live together in Los Angeles and married in July 2020.[17]
