When cranky secretary Ida Blankenship died in Mad Men's season four Bert Cooper memorialized her by saying: "She was born in 1898 in a barn. She died on the thirty-seventh floor of a skyscraper. She’s an astronaut." In the show's midseason finale, Cooper dies watching men walk on the moon.
Cooper wasn't necessarily a good man—his objection to seating Dawn at reception because she's black being a distasteful recent example of his more insidious qualities—but he was one of Mad Men's true originals, and one with a mischievous spirit. He was, as he tells Roger in last night's episode, always a leader, which means he could embrace his oddball tendencies: his interest in Japan, his hatred of shoes. His eccentricities at times obscured a shrewd and ruthless mind for the business, and, if we're going to be honest about it, the show regarded him as a secondary character, deploying only when necessary.
Cooper's send off—a post-death song and dance number visible only to Don—is as much of a tribute to the character as it is to his portrayer. Casting Robert Morse was the show's great inside joke, since Morse is an icon of the Mad Men era for having played How to Succeed in Business Without Really Trying's J. Pierrepont Finch both on stage and screen. The episode's conclusion is both a grace note to a longstanding character and something of a wink to the audience who knows Morse's musical theater history.