Charlie (The Truth)
Charlie was a fairly unsuccessful haberdasher in Pseudopolis when Mr. Pin found him. He wasn't successful because he was usually drunk and always a bit dim, but he had one valuable talent: he looked exactly like the Patrician of Ankh-Morpork. Mr Pin said he would pay a suspiciously large amount to have him do that for a few days.
The plot was not to substitute him for the Patrician; no, not Charlie. Not nearly reliable enough, would be Charlie. He was merely to appear to be the Patrician committing a crime, after which Tuttle Scrope could be elected Patrician and Charlie would be dispensible.
He was lucky enough not to be killed by Mr. Tulip or Lord de Worde's thugs and now does quite well as a children's entertainer, with occasional command performances when His Lordship wishes to be somewhere else. He reappears in Raising Steam, covering for Vetinari during the Patrician's unprecedented holiday (spent doing relaxing and enjoyable things on the railway. He has by now largely conquered his drinking habit and has learnt how to do the Voice and simulate the Patrician's idiosyncracies. However, Rufus Drumknott has taken care to call on Ishmael, who is tasked with monitoring Charlie just in case he gets unduly ambitious.
It is also revealed in Raising Steam that Charlie has a wife named Henrietta, a son named Rupert and a daughter. He has a 'special account' at the Royal Bank into which payments from the Palace go. Henrietta is delighted with the amount Charlie is earning for being Vetinari's double (described as enough to give his daughter a dowry fit for a queen, enable his son to enter any trade within the city, his wife to have her hair cut at Mister Fornacite's Salon like other wealthy women and provide better bedrooms for his children - they are currently saving up to afford a granny and granny flat) which is substantially more than what Charlie earns from puppet shows and clowning. This suggests his career - outside of impersonating Vetinari - may have taken a different direction from that suggested in The Truth, where it is stated he had enrolled in the Guild of Actors.