Olivia Swasey is an American voice actress based in Texas known for her work in English dubs of anime series. Born in Houston, Texas, she is the daughter of John Swasey, a professional actor, and Dena Swasey, a professional stage manager. Her interest in acting developed at an early age, and she began her career on stage, performing at HITS Theater in Houston where her first role was a Wickersham Brother in a production of Seussical: The Musical. After graduating from Westbury Christian School in 2018, she attended the University of Houston, earning a Bachelor of Fine Arts in Acting. During her time at university, she was part of the original cast for the world premiere of A Texas Carol at the A.D. Players and also studied at the Prague Shakespeare Company in Czechia. Since completing her education, she has worked across theater, voiceover, and video games.

Swasey has voiced a variety of characters in anime, often in productions by Houston-based studios. One of her notable roles is as Ylva, the strong-willed older sister of the protagonist in the historical epic Vinland Saga. She also played the ambitious and talented Maya Tendo in Revue Starlight, a role she found personally resonant due to the character's drive and her own background in performance. Other prominent credits include Echidna in I'm Quitting Heroing and roles in The Eminence in Shadows. Her voice can also be heard in additional voice work for series such as Chained Soldier and The Most Heretical Last Boss Queen: From Villainess to Savior.

A notable aspect of her career is her professional collaboration with her father, John Swasey, who is also a prolific voice actor and director. He directed her in Revue Starlight, and she has expressed that working together on projects they are both invested in is a special experience. Swasey has also discussed the camaraderie of working in voiceover, noting the fun and fellowship with colleagues at the studio. She has been attending fan conventions since 2020, which has allowed her to connect with fans and network within the industry. Her achievements include building a diverse portfolio of roles in a competitive field and being recognized for her character work in English-dubbed anime.