[1][2][3][4][5][6][7][8][9][10][11] Peggy Olson is initially presented as an innocent but determined young woman, eager to be a success in her job at Sterling Cooper after having graduated from the respected Miss Deaver's secretarial school.

"[15] In the pilot episode, "Smoke Gets in Your Eyes", which takes place in March 1960, Peggy begins work as a secretary for Don Draper (Jon Hamm).

Her supervisor, office manager Joan Holloway (Christina Hendricks), directs her in her duties as well as offers personal advice, which includes referring her to a gynecologist to obtain a prescription for birth control pills.

When Peggy initially meets account executive Pete Campbell (Vincent Kartheiser), he makes rude comments about her appearance, and Don defends her.

In "Babylon", Sterling Cooper executive Freddy Rumsen (Joel Murray) notices Peggy's sharp mind and creativity during a focus group for Belle Jolie lipstick.

The male account executives begin to mock her, and Joan makes unkind remarks to her about her appearance in an attempt to encourage her to lose weight and dismisses her success at copywriting.

When Peggy is promoted, she begins experiencing severe abdominal pain; she attributes it to a "bad sandwich" from the office cart and heads to St. Mary's Hospital in Brooklyn.

In the fourth season (1964–65), Peggy perseveres as a trusted member of the SCDP creative staff, despite lingering resentment and patronizing behavior from most of the men she works with.

Her affair with Duck has ended and she dates a young, weak-willed man named Mark (Blake Bashoff) but they break up when she chooses to work late instead of coming to a birthday dinner with her family he has planned.

Peggy then meets political journalist Abe Drexler (Charlie Hofheimer) through her new friend Joyce Ramsay (Zosia Mamet), a photo editor for Life magazine.

When Lucky Strike, SCDP's biggest client, ends their relationship with the firm, Peggy is responsible, essentially, for saving the company by signing Topaz Pantyhose.

She fails repeatedly to please Heinz Baked Beans's executive, and is finally removed from the account when she mimics Don's authoritative style but ends up offending the client instead.

In "The Flood", Peggy is nominated for a prestigious advertising award for her Heinz Baked Beans ad, which she developed with Draper's wife, Megan (Jessica Paré).

When Draper and Ted join forces to pitch Chevrolet, leading the two firms to merge, they turn to Peggy to draft the press release.

When Draper starts a new firm called Sterling Cooper & Partners, he asks Peggy to join, with the promise of greater creative control and a bigger salary.

Peggy has been unanimously declared Copy Chief but finds it very difficult to serve two masters, as she is almost continually put in the middle of Draper and Ted's leadership squabbles.

They grow further apart as his politics become more radical, and she becomes increasingly unhappy living in the building Abe suggested they buy, which is in a dangerous neighborhood, and decides to sell it.

The next morning, Ted asks Don to let him manage the SC&P office in California, in an effort to put as much distance between himself and Peggy as possible, and to achieve a fresh start with his family.

Draper's erratic attendance and behavior start to cause concern, and in the wake of a disastrous Hershey's pitch meeting, the partners place him on a leave of absence of unspecified duration.

Peggy is often openly resentful of Don's demanding requirements and his refusal to express appreciation for her work, but is also conscious that he is the only one in the firm who views her as an equal to her fellow copywriters, notwithstanding her gender.

When in "Maidenform" (Season 2) Peggy questions her male colleagues' categorizations of women as "Marilyns" or "Jackies", and asks which she is, Ken quips that she's Gertrude Stein, and the younger men laugh.

He assumes she will quit Sterling Cooper and follow him to his new agency, but is surprised and hurt when she declines, stating that she's tired of being on the receiving end of his anger when something doesn't work out for him.

Matthew Weiner, the series' creator, head writer, and showrunner, has stated that this conversation is essentially Don telling Peggy that he loves her.

Peggy interprets the gesture as a backhanded compliment, and in a private chat with Joan remarks indignantly that Don seems more excited about marrying his secretary than about her own success.

The other partners place Don on a forced leave due to his behavior, making Peggy SC&P's de facto creative director.

Peggy is still struggling with Burger Chef, and is further discouraged after Lou Avery and Pete Campbell tell her she needs to be "the voice of moms" with the campaign and that it must focus on a happy family life.

Peggy tells Don that she traveled to several different states and spoke to hundreds of Burger Chef customers, and begins to cry because she doesn't know what she did wrong with the campaign.

During Season 7, after Peggy learns SCDP has been absorbed back into McCann-Erickson, she considers leaving entirely, but a headhunter convinces her that she is better off moving to McCann and remaining there for a few years, until she's built up her resume.

Though frustrated by McCann's misogynistic culture and thrown by Don's sudden and unexplained departure, she is briefly tempted by Joan's proposal that they join forces and start their own agency.

However, in the final episode, Peggy ultimately decides to stay at McCann, in part to remain with Stan, as they come to realize that a mutual love has developed between them.