Mary O'Brady is a professional voice actor with over twenty years of experience in the industry. Her work spans commercials, corporate narration, documentaries, eLearning materials, and animation, including ADR and dubbing for anime and video games. She is also known for her work as a producer, director, and writer on various international corporate projects. O'Brady is a classically trained actor with a deep vocal range, often described as authoritative yet warm, which has made her a frequent choice for roles such as queens and villains, though she is also skilled in character comedy.

In the anime world, O'Brady is known for her role in the original sci-fi action series Bullet/Bullet. She provides the English dub voice for the character Qu-0213 Ay-baba in the show. The series takes place in a post-apocalyptic wasteland and follows a young junk shop worker named Gear and his companions, including a four-personality robot. In the original Japanese version, the character is voiced by Ai Orikasa.

Beyond this role, O'Brady has contributed to other animated series and films. She voiced the character Bilara in the fantasy adventure film Bayala - Das magische Elfenabenteuer. Her television voice credits also include the role of Cynthia in the series Hero Inside and Baba Yaga in Agenzia Segreta Controllo Magia.