"Nothing we did in the series was altered to save something for the movie," King said at the U.S. Comedy Arts Festival.
"This is exactly the way we wanted to end the series," he said Friday. "We're proud of what we did."
The HBO series, which aired its last new episode Feb. 22, will live on in syndication. That pleases star Sarah Jessica Parker, even if the episodes are toned down for a broader audience.
"I am not sad about a larger audience," said Parker, who played columnist Carrie Bradshaw. "Part of me is happy that people who could not afford HBO" will now have the opportunity to meet the four women whose love lives were chronicled on the show.
"We joke there will be no Samantha" after the censors have their way, writer Cindy Chupak said of the free-spirited character played by Kim Cattrall.
Parker, King, Chupak and the show's five other writers appeared at the comedy festival, which ended Sunday.
The writers, all women, described how their real-life experiences made their way into the scripts. In the sanctity of the writers' room, they discussed their dates and relationships.
"Very often that bleeds into story building," said writer Elisa Zuritsky.
Some of the writers said they share the characters' love of expensive shoes. Amy B. Harris acknowledged she has 50 to 75 pairs; Jenny Bicks' collection consists of about 30 pairs.
And Parker's shoe wardrobe? "I can't talk about it," she said with a laugh.