Guillaume Orsat is a French actor specializing in dubbing, as well as a voice director. Born in Paris on April 7, 1964, he is a trained performer who studied at the Conservatoire national supérieur d’art dramatique (CNSAD) and the École nationale supérieure des arts et techniques du théâtre (ENSATT). Beyond his work in animation, he is widely recognized as the regular French voice for actors such as Brendan Fraser, Nathan Fillion, Vin Diesel, and Dwayne Johnson, and he voices Groot in the Marvel Cinematic Universe films.

In the realm of anime and animated series, Orsat has contributed his voice to a variety of characters. He is notably the French voice of the Decepticon leader Megatron across the Unicron Trilogy of Transformers series. This includes Transformers: Armada, Transformers: Energon, and Transformers: Cybertron, where he also voiced the character Red Alert. A point of clarification from dubbing sources notes that in Transformers: Armada and Transformers: Energon, the character credited as Red Albert is in fact the character Red Alert.

Other prominent anime roles include Grimms, also known as the god of death, in the Netflix original series Sword Gai: The Animation and its second part, Sword Gai: The Animation Part II. He voiced Torgrim in the Netflix dub of the historical epic Vinland Saga and played Ichirō Watanabe in the animated film Napping Princess (also known as Hirune Hime: Rêves éveillés). His film work also extends to dubbed roles in major animated features, such as John Rolfe in Pocahontas II and Mack in the Cars film series.

In addition to his on-screen voice work, Orsat is active as a voice director, overseeing the French versions of numerous television series, including Breaking Bad, Better Call Saul, and Grimm.