Charlie is known to have bad luck. He is arrested for threatening to beat up local officials over the slow progression of HDTVs. He was briefly disabled as stated by Lenny after Homer notices he is not at the plant. However, he later recovered. He, along with other employees, were also set on fire due to Homer's negligence. As a member of the Springfield Nuclear Power Plant softball team, Charlie uses his sister's wooden leg as a baseball bat.
Charlie is replaced by Mindy Simmons after he, Homer, Lenny, and Carl play a prank on a worker and cause a radioactive gas leak and Charlie complains to Mr. Burns that the plant requires a real emergency exit rather than one which is painted on. Burns lowers a giant tube which sucks Charlie up, sending him to an Asian country where he is forced to dance on a table.
When Homer sees Charlie exiting the plant and asks if he wants a lift, Charlie declines. Stating that he got tipsy the night before and that he lost something of his, therefore waiting for and expecting a callback.
After some new, German owners take over the plant, Charlie is later seen arriving to work in a new car.
When Mr. Burns tells Homer that natural gas doesn't create worker mutating radiation, a mutated Charlie appears telling Homer to prepare to watch the game.
Charlie appears in a flashback where he attends a party and the Rollers Rink Couples Night. He appears to be with another woman who doesn't appear to be like his current wife. Although the woman might most likely be an ex-girlfriend of Charlie or his current wife had a completely different appearance. 
Characters in The Simpsons
Charlie bears a resemblance to Sam, one of the barflies at Moe's Tavern. This could be because they both have big glasses, they both have trouble with alcoholism, they have scruffy looks, worried eyes, and have bags under their eyes. They also occasionally are seen hanging out at Moe's Tavern as well.
Characters in other media
He is voiced by Dan Castellaneta, who said that he was "just [doing] an imitation of Lenny", according to the commentary for "Homer at the Bat". His voice sounds similar to the Blue-haired Lawyer, Arnie Pye and Louie, who are also voiced by Castellaneta.
Episodes where he has an actual role are in bold.