In the week leading up to the Mad Men premiere The Wire will be revisiting some of the show's most important characters, beginning with that whiny, childish account man, Pete Campbell. 

Who He Was

The audience first meets account executive Pete Campbell on the day of his bachelor party. He's an ambitious, 26-year-old little weasel, gunning for a higher position in the firm. Even in the pilot, it's evident that perhaps Pete is more sinister than your run-of-the-mill slimeball. The minute he sees Peggy, he evaluates her body. At a strip club, he tries to feel up a girl. When she tells him to stop, he continues pressing. He grabs her hand and she tells him he is hurting her. But Pete is also, from the beginning, surprisingly self aware. He famously goes to Peggy's apartment, drunk. "You must think I'm a creep," he tells her. 

Pete's struggle, even in the show's infancy, is how conscious he is of his worst qualities, and how he acts upon them anyway. Yes, he's a creep, but he knows he's a creep. 

Big Moments 

Season 1, Episode 12, Nixon vs. KennedyPete's ruthless ambition reaches its earliest heights, when he tries to blackmail Don into giving him the head of account services position after finding out the truth about Don's past as Dick Whitman. 

Season 2, Episode 2, Flight 1Next to Don, Pete has experienced some of the most large-scale personal tragedies of any one on the show, but those have been confounded by the deeply troubled relationship he has with his family. In this episode, his father dies on American Airlines Flight 1, a connection to the event he ultimately uses to try and help Sterling Cooper win the airline as a client. 

Season 3, Episode 8, Souvenir: One of the most notorious episodes for Pete, who drunkenly forces himself into the apartment of the German au pair that lives next door to him. After this episode aired, the media erupted into debate as to whether Pete raped the woman. Though the answer to that is ambiguous, he certainly forced himself into her life. 

Season 5, Episode 4, Signal 30Pete is careening to some unknown destination, even as he and Trudy have set up a seemingly idyllic life outside of the city. He flirts with a high school student, sleeps with an escort only after she calls him "king," and has a fistfight with Lane.  

Season 6, Episode 4, The FloodPete is routinely (somewhat surprisingly) one of the most progressive people at whatever iteration of Sterling Cooper is currently in play, especially when it comes to race. After Harry complains about how the death of Martin Luther King Jr. is impacting business, Pete blows up at him, calling him a racist. It's another strange instance of Pete being one of the most inhumanly humane people on the show. 

Who He Is Now

Pete began the show as a boy who can barely fit into his suits, he enters the final season as a man who is busting out of them. Of any character, Pete has physically changed the most. He's gotten pudgy, his hairline has receded. At the end of season six,  he plans to head to California with Ted Chaough. His relationship with Trudy has completely fallen apart. She is now completely wise to his ways, not to mention outraged after Pete tells her he found her father (one of Sterling Cooper's clients) at a whorehouse. His mother, afflicted with Alzheimer's, is now dead, having been lost at sea while on a trip with Manolo, her nurse and Bob Benson's friend. 

Pete is arguably the most interesting character on Mad Men. Whereas Don is all brooding mystery, Pete is all sneering id. He started out the show wanting a blessed life—the perfect wife, the high powered job—but was foiled at every turn by his own instincts. Now he is free of the WASP expectations that have governed so much of his existence. Pete begins the new season in high spirits, but his basest instincts are probably not gone.