Charles "Charlie" Kelly is a fictional character on the FX series It's Always Sunny in Philadelphia, portrayed by Charlie Day. Charlie is co-owner and janitor at Paddy's Pub (although he later sells his shares) and a childhood friend of Mac and Dennis. He is also Frank's roommate and possibly his biological son.
Charlie is known for his illiteracy, his habit of slipping into a variety of characters for his various schemes, and his never ending obsession with The Waitress. Although he is by most respects the stupidest member of the Gang, he is capable of rare, impressive moments of brilliance, particularly with music and engineering complex social schemes. The most tedious and disgusting janitorial tasks at the bar are referred to as Charlie Work, even when Charlie is temporarily spared from performing them.