Carrie Bradshaw on "Sex and the City" called her sometimes-boyfriend and eventual husband Mr. Big because she and her friends thought he lived a big life with his career and personal activities. He frequently spent big amounts of money, dated a number of women and lived in a large New York City apartment.
Traditionally, it was only in voiceovers that he was referred to as Mr. Big. Carrie and her friends shortened it to Big. It was not until the final season of the television show "Sex and the City," in the finale "An American Girl in Paris Part Deux," that his name, John, was revealed via Carrie's cell phone. In the first "Sex and the City" movie, his full name was revealed to be John James Preston. The author of the "Sex and the City" novels, Candace Bushnell, said that Mr. Big was based on the former publisher of GQ and Talk, publishing executive Ron Galotti. In an interview with New York Magazine, she also said that she called him Mr. Big because he was like the big man on campus in New York City.
Mr. Big was the only one of Carrie's boyfriends who she used a nickname with, excluding her use of surnames.