Mad Men’s Don Draper has a checkered past and a secret identity that, once revealed, have a knock-on effect throughout the whole series.

Don Draper's checkered past and secret identity significantly affected his character arc across Mad Men's seven-season run. Chronicling Don’s life over a period of ten years, the show juxtaposes glitz and glamour with despair and desperation, painting a complex character that harkens back to the noir fiction that Don (Jon Hamm) would have grown up around. He begins the series as the hot-shot Creative Director of Sterling Cooper, an advertising agency in 1960s New York, but spirals into an identity crisis after being forced to confront his past sins.

While Don's bad habits (namely smoking, drinking, and cheating on his wife) are on full display in the early half of season 1, Don's past lurks in the shadows. On the outside, he's a made man - devilishly handsome and chillingly confident; with a wife and two kids in the suburbs; along with a well-paying job in a lucrative industry -  but we slowly discover that it's all an act. Don takes to existential brooding, intensely and often. He makes rash decisions in the heat of the moment and drinks whiskey before breakfast. The so-called "American Dream" is clearly not all it's cracked up to be, and the audience is encouraged to examine its paper-thin facade.

After a run-in with his estranged half-brother, Adam (Jay Paulson), Don has flashbacks to his childhood during the Great Depression. Back then, his name was Dick Whitman - the illegitimate son of a prostitute and a drunk; dirt poor, and abused by his stepmother. Adam mails Don a shoe-box containing memorabilia from his former life - including letters, photographs, and dog tags - after Don gives him $5,000 to leave New York and cease contact. The delivery is intercepted by Pete Campbell (Vincent Kartheiser), Don's suspicious underling, who takes the shoe-box home. He discovers Dick Whitman died in Korea ten years prior, and the real Don Draper disappeared around the same time. In episode 12, "Nixon vs. Kennedy", Pete attempts to blackmail Don with this information, but is foiled when company co-founder Bert Cooper (Robert Morse) brushes the whole thing off. Don, finally confronted with his past, has a flashback to the Korean War. As Dick Whitman, he was a soldier serving under Lieutenant Don Draper. It is revealed that the real Don died in an explosion and Dick assumed his identity, taking the chance to end his service early and sever all ties to his previous life, along with its associated traumas.

While the decision to reveal Don’s identity via flashback could be seen as un-dramatic (information conveyed only to the audience and not to other characters within the narrative), it solidifies the viewer as Don’s confidante. This charges the narrative with dramatic irony, wherein the audience knows more about Don’s past than the other characters do. This produces tension whenever Don’s mask threatens to slip because we know the stakes. We know how much he has to lose, and - as mirrored in the iconic title sequence - we know how far he has to fall.

This reveal in “Nixon vs. Kennedy” is crucial to Don’s character arc throughout the rest of Mad Men's run. While his past remains relatively unknown to those around him, the lid is, quite literally, off the box, and - as fans of Greek myth will know - that box contains demons. Don’s character arc throughout the rest of the series essentially boils down to ‘solve et coagula’ - an alchemical phrase, which translates from Latin as ‘dissolve and coagulate’. For Don, this process involves examining each of his separate identities - Don Draper and Dick Whitman - before fusing them together, thus creating a new identity. For Don, this is the only way to achieve inner peace. As such, the shameful reveal of Dick Whitman marks a crucial turning point in Don’s journey; the crossing of a threshold that will lead to his spiraling downfall, and - ultimately - his re-birth and redemption.

Next: Mad Men: The Actors Who Almost Played Don Draper