Charles Peckham Day (born February 9, 1976) is an American actor, writer, producer, and podcaster. He is best known for playing Charlie Kelly on the FX comedy
It's Always Sunny in Philadelphia (2005–present), which he co-created with Rob McElhenney and Glenn Howerton, and of which he is also a writer and an executive producer. In 2011, he was nominated for a Critics' Choice Television Award and a Satellite Award for the role. He subsequently co-created the Fox sitcom
The Cool Kids (2018–2019) with Paul Fruchbom and the
Apple TV+ comedy
Mythic Quest (2020–present) with Rob McElhenney and Megan Ganz, and continues to executive-produce the latter. In film, Day is best known for his performances as biologist Dr. Newton Geiszler in Guillermo del Toro's science-fiction monster movie
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