Jillian was born in La Canada, California, a small suburb in Los Angeles. She went to the University of California, Berkeley to play collegiate volleyball and went on to train with the USA women's indoor volleyball team.
She began her acting career by taking improv classes at the Upright Citizens Brigade and The Groundlings, and quickly transitioned into commercials, and later television. Jillian has written and produced original content, including a PSA starring Kristen Bell, and a short film featured in the 2018 HBO Women in Comedy Festival.
When she's not acting and writing, Jillian loves to play volleyball, tennis, and ski. She lives in Los Angeles.
