Swartzwelder started out with a career in advertising. He sent a joke submission to the writers of "Late Night with David Letterman" in 1983, which he signed but left no address. Writer Jim Downey traced Swartzwelder based on the Chicago postmark on the card via phone books at the New York Public Library. After he contacted Swartzwelder's mother in Seattle, she redirected him to her son, who was then working at an advertising agency in Chicago. Downey described Swartzwelder's interview as "one of the most spectacularly awful in history," as it consisted of him entering David Letterman's office without permission, and discussing the state of television (that it was "all shit") while smoking and drinking. He was not hired for "Letterman", but Downey hired him for "Saturday Night Live" beginning in 1985.