Marianne Miller is an American voice actress known for her extensive work in anime dubbing, animation, and video games. Based in Los Angeles, she began her career in the mid-2000s after deciding to pursue voice acting over on-screen or theatre work. At the age of 19, she received a call from voice director Mike McFarland to record background voices for Fullmetal Alchemist the Movie: Conqueror of Shamballa in Dallas, Texas, which marked her first professional voice-over role. Following this initial opportunity, she moved to Los Angeles to study and train, building a career that would encompass a wide variety of characters.

Miller has been credited in numerous prominent anime series. One of her earlier notable roles was as Yuuno Scrya in Magical Girl Lyrical Nanoha and its sequel, Magical Girl Lyrical Nanoha A's. She also voiced Kyosuke Kamijo in the critically acclaimed series Puella Magi Madoka Magica. In the Fate franchise, she is recognized as the voice of Enkidu in the English adaptation of Fate/Grand Order -Absolute Demonic Front: Babylonia-. Her work extends to fantasy series such as The Seven Deadly Sins: Imperial Wrath of The Gods, where she voiced Gloxinia, the former King of the Fairies. In the Netflix original anime B: The Beginning Succession, she provided the voice for the character Izanami.

Beyond these, Miller's filmography includes a range of other significant roles. She voiced Recon (Shinichi Nagata) in Sword Art Online, as well as characters in Fate/Zero, Moribito: Guardian of the Spirit, and Tweeny Witches. In the series The Familiar of Zero, she voiced the character Malicorne. Her work in original English animation and Netflix projects includes the role of Bridge in the series Cannon Busters and Phantoma in the film Hells. She is also well-known for her performance as the spirited witch Amanda O'Neill in Little Witch Academia: The Enchanted Parade, a role she would reprise in the subsequent television series.

Throughout her career, Miller has demonstrated a versatility that allows her to portray young boys, adult men, and female characters across various genres. Her work frequently involves collaborations with other voice actors and production studios in the Los Angeles area. In her personal life, she is married to Martin Billany, a YouTuber known for creating the Yu-Gi-Oh: The Abridged Series.