Charlie Day was born in New York City and spent most of his childhood in Middletown, RI. Both of his parents taught music in Rhode Island, which likely influenced the future star's keen interest in music and the performing arts. Day attended The Pennfield School and Portsmouth Abbey School in nearby Portsmouth prior to attending Merrimack College in North Andover, MA where he also played baseball. He made his onscreen acting debut with a minor role in the ABC television movie "Mary and Rhoda" (2000), which reunited old friends Mary Tyler Moore and Valerie Harper, co-stars of the legendary comedy series, "The Mary Tyler Moore Show" (CBS, 1970-77). Day spent most of the early 2000s appearing in various independent films and on a variety of television shows, landing his first regular role on the short-lived situational comedy "Luis" (ABC, 2003) and a recurring character appearance on the crime drama series "Third Watch." On the latter, Day played the brother of actor Jason Wiles' character, a New York police officer who grew up with an abusive father.In 2005, Day began starring on the FX comedy series "It's Always Sunny in Philadelphia," about a group of longtime foul-mouthed, would-be cosmopolitan slackers (Day, Glenn Howerton, Rob McElhenny, Kaitlin Olson) running a Philly bar and bumbling through weekly sequences of flinch-inducing buffoonery. Day's character of the hot-blooded Charlie Kelly, a hardworking yet underachieving co-owner of the bar, soon became an audience favorite for always taking on the establishment's most tedious and filthy janitorial tasks, referred to by the other characters as "Charlie Work." A fan of the show, Danny DeVito joined the cast in the second season, which helped boost the show's ratings. Made on a shoestring budget and with seemingly all odds stacked against it, the struggling show was eventually embraced by a rabid following for its relentless disregard for politesse and a conspicuous lack of any redemptive character traits."It's Always Sunny in Philadelphia" had originated as a short film idea that developed into a TV pilot shot on a digital camcorder by Day and his co-stars Howerton and McElhenny. The first season aired in 2005 and slowly generated buzz among TV viewers. Day also served as the one of the show's producers, writers, and because of his musical background, contributed music for several episodes. Not long after "Sunny" premiered, in 2006, Day married actress Mary Elizabeth Ellis, who would play "The Waitress," a recurring character and Charlie's object of affection. The couple first met on the set of "Reno 911" (Comedy Central, 2003-09), where they played a pair of incestuous siblings. Day made the leap to mainstream features in 2010 with a supporting role opposite Drew Barrymore and Justin Long in the romantic comedy "Going the Distance." The following year, he co-starred with Jennifer Aniston and Jason Bateman in "Horrible Bosses," a dark comedy about friends who conspire to murder their overbearing managers.The summer of 2013 turned out to be a banner season for Day, with two major movie projects seeing release within next weeks of each other. First he lent his voice to the oddball character of Art for the hit Pixar prequel "Monsters University," and then appeared in the giant robot spectacular "Pacific Rim" as relentlessly curious scientist Newton Geiszler, a researcher fascinated by the Kaiju creatures that threaten the world.