Vanessa Marshall attended Princeton University, majoring in English. She then attended graduate school at the New York University Tisch School of the Arts, attaining a masters in acting and learning different dialects, which Marshall credits for helping her in her voiceover career. She started voice acting after being discovered by a voice acting agent during a solo performance, where she was playing 15 different characters.
One of her best known roles is her voice acting for the character Hera Syndulla in Star Wars Rebels. She reprised the role in Star Wars: The Bad Batch.