Emerson Foote, the F in modern-day agency FCB, famously resigned from his post as chairman of McCann-Erickson in 1964 because he didn't want to promote the sale of cigarettes. This bold move was later copied (sort of) in Mad Men's fourth season, when Don Draper took out a full-page ad in the New York Times to explain why Sterling Cooper Draper Pryce would no longer accept clients that sold tobacco.
Of course, Draper's declaration came shortly after his firm lost its big tobacco account, Lucky Strike, while McCann-Erickson was still advertising cigarettes in international markets when Foote decided to step down. Earlier in his career, Foote had worked on the Lucky Strike account, just like Draper.
Foote was also once director of the American Cancer Society, an agency whose fictionalized counterpart began working with Draper's firm after being impressed by his letter in the Times. The show even went so far as to have Draper's secretary let him know someone named Emerson Foote had called for him after the letter ran.
Foote passed away of complications related to appendicitis in 1992.