If not, when did this sort of character start to appear? I know there wasn't a ton of fictional entertainment in medieval times, but I'm just curious as to how this archetype might appear in such an old setting, without sunglasses, cigarettes, motorcycles and hip rebellious youth.
In the French fabliaux Du Foeteur ("The Fucker") there's something similar to a "bad boy" in the sense you're talking about.
A rich woman's husband leaves their house and goes to do business in the city. After her husband leaves, the woman and her maid see a handsome, well-dressed young man sitting on a bench across the street. The wife tells her maid to go ask the handsome young man who he is. The maid speaks with him and returns to her mistress, telling her that the man is a male prostitute and he will have sex with the lady for a set fee.
The wife invites the man in, they sleep together, and just as she's paying him, they hear footsteps--the husband is back early. The wife begins freaking out, but the young man tells her to calm down and draw a hot bath and for her to run out of the back door. She draws the bath and leaves.
The husband enters the house and sees the man in the bathtub and defensively asks who he is. The young man says that he is a prostitute who was going to have sex with the man's wife, However, if the husband pays him the agreed upon amount, then he will leave, thus leaving the wife's virtue in tact.
The young man takes the husband's money and the wife's money and leaves with double his fare.