Here's a rundown of the cast and characters of It's Always Sunny In Philadelphia. The show began back in 2005 on FX, with It's Always Sunny In Philadelphia following the gang of losers running dive bar Paddy's Pub. It's a sitcom with a particularly dark brand of humor, but despite drawing a cult it wasn't much of a ratings hit during the first series. The network invited Danny DeVito to come onboard during season 2, which helped improve viewing figures to survivable levels.

Against all odds, It's Always Sunny In Philadelphia is now one of the longest-running live-action sitcoms of all time, beating out the likes of Cheers. This is despite the fact the main characters are all - without exception - horrible people, but the show has managed to keep them oddly likable over the course of fourteen seasons. The show isn't confirmed for another series yet, but despite the cast being busy on other projects - such as Glenn Howerton on A.P. Bio - it will almost certainly return at some point.

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It's Always Sunny In Philadelphia's gang haven't necessarily evolved as human beings over the last fifteen years, but the actors playing them have really grown into their roles. Here's a cast and character rundown for the show.

The Its Always Sunny Gang Squashes Their Beefs Gang Screenshot

Glenn Howerton - Dennis Reynolds

Glenn Howerton (The Hunt) is It's Always Sunny In Philadelphia's Dennis, co-owner of Paddy's alongside Charlie and Mac who is a vain, sex-obsessed sociopath. Dennis enjoys playing mind games on family, friends and lovers alike, and famously pioneered the horrid D.E.N.N.I.S. system. While he has brief flashes of humanity, he's arguably the most dangerous of the gang.

Kaitlin Olson - Dee Reynolds

The Mick's Kaitlin Olson plays Dee on It's Always Sunny In Philadelphia, Dennis' twin sister. On paper, she should be the most sympathetic as Dee's constantly bullied and belittled by them, but she's soon shown to be as vain and selfish in pursuit of being liked. She wants to be an actress or stand-up comic despite having no real talent for either and is just as hopeless in a romantic relationship as the others.

Rob McElhenney - Ronald "Mac" McDonald

Rob McElhenny plays Mac, who serves as the bouncer on It's Always Sunny In Philadelphia. Mac has an inflated image of his own masculinity and frequently talks about religion and morality despite rarely living up to his own high standards. Mac's weight has gone up and down through the show, becoming obese in season 7 before becoming super ripped in season 13. After years of denying it to himself, Mac finally came out as gay during season 12, and in one of the show's more moving storylines, tried to break that news to his convict father through dance.

Charlie Day - Charlie Kelly

Pacific Rim co-star Charlie Day is Charlie on It's Always Sunny In Philadelphia. Charlie does most of the hard work in the bar, including repairs and cleaning, and has horrible hygiene, liking to venture into the sewers for the sheer fun of it. He's also obsessed with "The Waitress" and spends seasons pursuing her, despite her utter repulsion towards him. Despite being depicted as the dumbest member of the gang he's a surprisingly good songwriter, even writing musical The Nightman Cometh in season 4.

Danny DeVito - Frank Reynolds

Danny DeVito joined It's Always Sunny In Philadelphia during the second season as Frank, Dennis and Dee's father. It's later revealed he's not their real father, but he might be Charlie's, with the two becoming roommates. He was kicked out of his own successful business, but despite being rich he seems to love living in filth with Charlie. Like Dennis, he also has an unhealthy relationship with sex and is frequently the one to cook up the gang's many misguided schemes.

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