The third season of the American television drama series Mad Men premiered on August 16, 2009, and concluded on November 8, 2009. It consisted of thirteen episodes, each running approximately 48 minutes in length. AMC broadcast the third season on Sundays at 10:00 pm in the United States.

Season three takes place six months after the conclusion of the second season (roughly April/May 1963) and ends on December 16, 1963.^[1] It covers the end of Kennedy's "Camelot era" in the country, and chronicles the characters going through immense change in their professional and personal lives.

The third season was exalted by television critics and was a major winner in many television awards. Mad Men won the Primetime Emmy Award for Outstanding Drama Series, Golden Globe Award for Best Drama Series, and acknowledgement by the American Film Institute for the third year in a row. According to year end lists collected by Metacritic, Mad Men was the most acclaimed show of 2009.^[2]

The season opens six months after the Cuban Missile Crisis. Don and Sal then leave for a business trip to Baltimore, where Don cavorts with a flight attendant. Sal, meanwhile, has an intimate moment with their hotel's bellboy. After the fire alarm is set off, Don sees Sal with the young man. Don keeps it to himself, then pitches Sal a new advertising tagline, ostensibly for London Fog raincoats — "Limit your exposure".

Pete is offered the role of Head of Accounts by Lane Pryce, a PPL executive brought in from the London office. Pete is ecstatic until he learns that he will be sharing the title and the responsibility with Ken Cosgrove. At a country club party that Roger and Jane throw, Don and Betty both connect with strangers. Don strikes up a conversation with a man who turns out to be Conrad Hilton, founder of Hilton Hotels. Betty has a friendly conversation with an affable man named Henry Francis, who works for Governor Rockefeller. Roger, meanwhile, takes issue with his daughter, Margaret, who does not want her 20-year-old stepmother, Jane, at her wedding, scheduled for November 23, 1963.

Betty's father Gene, suffering from his strokes, comes to live with the Drapers and strikes up a warm relationship with Sally, even teaching the young girl to drive. He is frustrated, though, by Betty not wanting to face up to the practical details of his death. Gene soon dies, and Sally scolds her parents and Betty's relatives for their apparent lack of grief at his demise. Betty gives birth to a boy, named Gene over Don's strenuous objections.

Days before Joan's last day at the company, her husband Greg returns home drunk, telling her that he was passed over for an important promotion and that he has been unofficially blacklisted by his teachers from being a professional surgeon in New York City due to his subpar surgical skills, and demands she get another job.

Executives from Putnam, Powell, and Lowe travel from London to tour the Sterling Cooper offices and to present a new organization plan that places the agency under a new up and comer, Guy MacKendrick, effectively sidelines Sterling and Cooper, and transfers Pryce to Bombay. After the announcement, Lois loses control of a John Deere tractor and runs over MacKendrick's foot. MacKendrick is presumed unable to perform his duties and Pryce is informed that he will keep his job in the States in the interim.

Conrad Hilton starts harassing Don with late night phone calls, seeking off the books help with regard to advertising for his companies. Don finds it both flattering and overwhelming, as he struggles to create quality material. When Connie learns Don has no contract tying him to the agency, Cooper uses his knowledge of Don's assumed identity to pressure him into signing a contract so as to retain Hilton's interest.

Betty enlists Henry's help with a neighborhood petition, and becomes smitten with him. She begins sending him letters and meeting with him in secret. Elsewhere, Don begins having an affair with Suzanne Farrell, Sally's teacher. During this period, Duck Phillips tempts both Pete and Peggy with business overtures to entice them to come to work with him at Grey; while neither accepts the business proposition, Peggy does accept Duck's initiation of a sexual relationship with her.

While on a shoot for a Lucky Strike commercial, Lee Garner, Jr., makes a sexual advance toward Sal. Sal refuses, causing Lee to call Sterling Cooper and demand his firing. Roger instantly fires Sal due to Lucky Strike's importance with the company. When Sal goes to Don for help, Don expresses little sympathy.

Betty breaks into the drawer to the desk in Don's den. She finds his box of Dick Whitman's family photos as well as evidence of Anna Draper's existence and Don's divorce from her. She confronts him. Don is forced to divulge the secret of his former identity and his desertion in Korea.

Pete becomes despondent when alerted by Lane Pryce that Ken is to become Senior Vice President in charge of Account Services. The news of the assassination of John F. Kennedy hits the day before Roger's daughter gets married. Pete is adamant about leaving the agency and mourns Kennedy on the couch with his wife. Greg informs Joan that he is enlisting to become an Army surgeon. When Betty is confronted with the lies her husband has told her regarding his identity and infidelities as well as her own growing attraction towards Henry, things come to a head with the Drapers following the assassination of the president. Don's inability to connect to Betty's emotional grief over the death of the President leads Betty to tell Don that she doesn't love him anymore and that she wants a divorce.

Connie meets with Don to inform him that Sterling Cooper and PPL both are being bought out by McCann Ericson, the firm handling Hilton's other accounts. Infuriated, Don returns to the office and begins hatching plans with Cooper and Sterling to buy the company. When their offer is rebuffed, Don realizes that Lane's authority to fire the other conspirators would sever their contracts, giving them the ability to walk away and start a new advertising agency. Lane agrees with the scheme and becomes a partner. Don and Roger start reaching out to other employees to join their new agency, including Pete and Peggy.

While drinking with Sterling, Don learns about Betty's relationship with Henry Francis and confronts her physically. However, Don later calls Betty and tells her that he will not fight the divorce. Betty leaves with the baby and Henry to get a divorce in Reno. Don, Peggy, Roger, Bert, Lane and Pete subsequently break into the Sterling Cooper office to take necessary supplies and files. Joan and Harry are soon called in to join the company and help them. The group meets in a small hotel room, where Joan answers calls with the name of the new firm: Sterling Cooper Draper Pryce.