The film's writer David Koepp said of the meaning of the movie's "Black Bag" title: "I sort of made that up because I thought it sounded cool. There was a film producer who I knew in New York who would say, 'That goes in the black bag', whenever he got something bad or negative that he didn't like. You throw it in the black bag, then you throw the bag in the river and never see it again. I like that as a metaphor for where things go that are never going to be discussed. I re-purposed it as a piece of spy slang that doesn't actually exist - but maybe it should."
Scriptwriter David Koepp consulted with real-life spies, assets, agents, and operatives in order to write this spy movie.
Director Steven Soderbergh said that he chose Michael Fassbender to play the keenly observant cyber-security interrogator George Woodhouse because he "...knew he wouldn't be afraid to play the interiority of George. He burrowed in deep while creating a calm surface that masks a lot of turbulence. Michael can imply a great deal without being flashy."
Alicia Vikander, wife of Michael Fassbender (George), made a playlist that was used in the film. She is given a 'special thanks' billing for this in the closing credits as "DJ Vicarious". In 2020, Vikander, with her agent, founded a production company called "Vikarious".
Writer David Koepp said: "All the spy craft stuff was very cool, but I learned more than I ever expected about the people." He added: "One woman told me that her job made it impossible for her to sustain a relationship. A line in the movie was inspired by his conversations with her. It was: "When you can lie about everything, how do you tell the truth about anything?". Koepp continued: "Think about it. If you want to have an affair, it couldn't be easier. You just say, 'I'll be gone for three days and you can't ask me where I'm going because you don't have clearance.' You can't trust people and people can't trust you. For George (Michael Fassbender) and Kathryn (Cate Blanchett), the confidential information they can't share goes into what they call their 'black bag'."