Shane Black and co-writer Anthony Bagarozzi began work on The Nice Guys, four years before the release of Black's Kiss Kiss Bang Bang. Their initial plan was that Black would focus on one character (Black with March and Bagarozzi with Healy), however that plan changed. The two eventually swapped the characters they would work on and wrote a first draft. In writing the script, they drew on the films Vanishing Point and Five Easy Pieces, as well as the novels of Brett Halliday. After they failed to sell the script, Black again reworked the script for a T.V. pilot. This, too, ultimately didn't go anywhere as CBS, the most interested party in the script, because they became concerned with its risque content. Ultimately, the script they finished at that time was radically different from the script viewers eventually saw on screen.
The script sat until 2009, when Bagarozzi approached Black and suggested that they change the film setting from the present day to the 1970s. This change helped to, as Black put it, provide a contrast to "the divisiveness that we see now."
A spiritual sequel to Kiss Kiss Bang Bang, The Nice Guys was an undeniable passion project for Black.
