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."
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.
Lead actress Cate Blanchett agreed to star this picture without even reading the script. She commented: "I just said, 'Who am I playing?' She added that that she quickly hopped on board. "It was written by David [Koepp] and directed by Steven [Soderbergh]. That's all I needed to know." She elaborated: "Steven's got amazing panache and range as a filmmaker." Blanchett continued: "He doesn't stay in the same lane. He understands the outsider's perspective these characters have, the way they can move almost panther-like through the world."
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".