Peggy Olson has succeeded, professionally, in a man's world.
She's a junior copywriter at Sterling Cooper and has shown little remorse for the child she never cared for; her family takes care of the son she had with Pete.
Peggy hails from Brooklyn and is sort of Don's protege. He woos her into his new company at the conclusion of season three.
Stan: Now we all know you don't have plans for Valentine's Day.
Ginsberg: She has plans, just look at her calendar. Friday, February 14th. Masturbate gloomily.
You'll have to believe me that I'll forget this. I don't want you treating me badly because I remind you of it.Peggy