Casey Mongillo is an American voice actor known for a wide range of roles in anime, animation, and video games. With a career spanning from the mid-2000s, Mongillo has become a prominent voice in English dubs, particularly recognized for portraying complex and youthful characters.

Mongillo's career gained significant attention in 2019 when they voiced the lead character Shinji Ikari in the Netflix English dub of the iconic series Neon Genesis Evangelion. This performance, which replaced the original ADV Films dub, was met with critical praise and introduced Mongillo to a broader international audience. Noel Kirkpatrick of TV Guide commended Mongillo's ability to switch "between sarcasm and sadness, delight and detachment," capturing the character's pre-teen voice effectively. For this role, Mongillo was nominated for Best Performance by a Voice Actor (English) at the Crunchyroll Anime Awards. Prior to this breakout role, Mongillo had been active in the industry since 2006, contributing voices to various projects including the web series PvP and the animated series TOME: Terrain of Magical Expertise.

Mongillo has an extensive and diverse anime filmography. Among their many roles are those specified by the user, including Kyouya Sasajima, also known as Wrath, in So I'm a Spider, So What?; Emporio Alnino in JoJo's Bizarre Adventure: Stone Ocean; and Cody in Fena: Pirate Princess. They also voiced Nene Onemine in Komi Can't Communicate, Theoto Rikka in 86, and reprised the role of Shou Suzuki in Mob Psycho 100 II. Further demonstrating their range, Mongillo voiced Isao Kasuga in Gleipnir, Charlot D. Hortensia in Hortensia Saga, Haru Shiokane in Tribe Nine, and Preces in K: Seven Stories.

Mongillo is also a significant part of the Pokémon franchise's English voice cast. They voiced the trio of Scorbunny, Raboot, and Cinderace belonging to the character Goh in Pokémon Journeys: The Series. Additionally, they lent their voice to the character Allister in the web series Pokémon: Twilight Wings. Their other notable anime roles include the Angel Devil in Chainsaw Man, Chilchuck Tims in Delicious in Dungeon, and young Manjirō Sano in Tokyo Revengers.

Beyond anime, Mongillo has an extensive body of work in video games. Some of their most prominent game roles include the Protagonist in Shin Megami Tensei V, Crow in Tower of Fantasy, Mustang in Goddess of Victory: Nikke, and Floofty Fizzlebean in Bugsnax. They have also voiced characters in major titles such as Red Dead Redemption, Ys IX: Monstrum Nox, and Fire Emblem Heroes. Mongillo has also done dubbing work for other media, such as the French series Osmosis for Netflix.

Throughout their career, Mongillo has worked with various dubbing studios and directors, becoming a familiar voice for fans of English-dubbed anime and video games. Their filmography demonstrates a consistent presence in the industry and a versatility that allows them to portray a wide spectrum of characters, from young, energetic Pokémon to complex, psychologically nuanced figures.