He directed and produced the web series There Will Be Brawl, based on the Super Smash Bros. His work has expanded to a multitude of roles in cartoons, video games and radio commercials. He has been a guest at conventions around the world, hosting at events such as Anime Expo and Anime Matsuri. Mercer began his career performing English walla and additional characters in several Japanese anime, and has since also worked in cartoons, video games, and radio commercials. He had a stint as a member of The Groundlings.

He decided to adopt 'Mercer', which members of his family had used in the past, as his stage surname because his birth name was too similar to someone already represented by the actor's union SAG-AFTRA. He spoke with a stutter when he was young his father, who also stuttered, got him a speech therapist who reduced the effects to the point that only certain words trigger it. He has a brother who writes and performs music under the stage name Dave Heatwave.

He attended Agoura High School in Agoura Hills, California. His family moved to Los Angeles when he was eight. Mercer was born Matthew Christopher Miller in Palm Beach Gardens, Florida, on June 29, 1982, to a family of Scottish descent. He is also a game designer and the chief creative officer of Critical Role Productions. In addition to his voice acting work, Mercer has developed and served as the Dungeon Master for the Dungeons & Dragons web series Critical Role since 2015. Kennedy in Resident Evil 6, Kurtis Stryker in Mortal Kombat 9, Chrom and Ryoma in Fire Emblem, Jack Cooper in Titanfall 2, Espio the Chameleon in Sonic the Hedgehog, Deadshot in Injustice 2, Cole Cassidy (Jesse McCree) in Overwatch, Yusuke Kitagawa in Persona 5, MacCready in Fallout 4, Midas and Syd in Fortnite: Battle Royale and Fortnite: Save the World respectively, Edér Teylecg and Aloth Corfiser in Pillars of Eternity, Gangplank and Kindred's Wolf in League of Legends, Walter in Shin Megami Tensei IV and Ira from Kingdom Hearts. In anime, Mercer voices Levi Ackerman in Attack on Titan, Kiritsugu Emiya in Fate/Zero, Jotaro Kujo in JoJo's Bizarre Adventure, Aikurō Mikisugi in Kill la Kill, Kanji Tatsumi during the second half of Persona 4: The Animation, the second voice of Yamato and Pain in Naruto, Trafalgar Law in the Funimation dub of One Piece, Hit in Dragon Ball Super, Seijirou Kikuoka in Sword Art Online, Falco in ‘’ Cyberpunk: Edgerunners’’, and Leorio in Hunter x Hunter. He is best known for his work with Studiopolis, Funimation, Bang Zoom! Entertainment, Viz Media, and NYAV Post in anime, cartoons, and video games.

Matthew Christopher Miller (born June 29, 1982), better known as Matthew Mercer, is an American voice actor.

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