Charlie Day, born Charles Peckham Day on February 9, 1976, in New York City, New York, is an acclaimed American actor, writer, and producer. He is best recognized for his portrayal of Charlie Kelly on the dark comedy series It's Always Sunny in Philadelphia, which debuted in 2005 and continues to be a cultural phenomenon. Alongside his role as an actor, Day also serves as a writer and executive producer for the show, contributing significantly to its unique blend of humor and outrageous storylines. His work on the series earned him nominations for a Critics' Choice Television Award and a Satellite Award in 2011, solidifying his status in the entertainment industry.

Raised in a family that encouraged creativity, Day is the son of Dr. Thomas Charles Day and Mary Peckham. He attended the University of California, Santa Barbara, where he honed his craft in theater. Day's early career included roles in various theater productions and guest appearances on television, but it was his breakthrough role on It's Always Sunny in Philadelphia that catapulted him into the limelight. The show's unconventional style and sharp writing resonated with audiences, allowing Day to showcase his comedic talents fully.

In addition to his work on television, Charlie Day has made a significant impact in film. He gained recognition for his roles in Horrible Bosses (2011) and its sequel Horrible Bosses 2 (2014), where he displayed his comedic range alongside stars like Jason Bateman and Jennifer Aniston. He also portrayed Dr. Newton Geiszler in Guillermo del Toro's visually stunning science fiction film Pacific Rim (2013), further diversifying his roles and demonstrating his versatility as an actor. Day's voice work is notable as well, with contributions to animated films such as Monsters University (2013) and the popular The Lego Movie franchise, where his distinctive voice brought characters to life. Most recently, he lent his voice to Luigi in the animated adaptation of The Super Mario Bros. Movie (2023), appealing to a new generation of fans.

Continuing his exploration of creative avenues, Day co-created the Apple TV+ comedy series Mythic Quest with Rob McElhenney and Megan Ganz, which premiered in 2020 and has been well-received for its clever humor and relatable characters. In 2023, he made his directorial debut with the film Fool's Paradise, showcasing not only his acting chops but also his storytelling abilities behind the camera.

Outside of his professional endeavors, Charlie Day has maintained a stable personal life. He married actress Mary Elizabeth Ellis on March 4, 2006, and the couple has since welcomed children, balancing family life with a thriving career in entertainment. Day's journey from a theater enthusiast in New York to a celebrated figure in television and film illustrates his talent, resilience, and dedication to his craft, making him a beloved and influential figure in the industry.