First Signal's promotional poster was designed by Daniel Elek-Diamanta. Diamanta, who is also a film composer, scored Mark Lund's Justice Is Mind (2013) and Serpentine: The Short Program (2017). The star field was designed using Celestia, a 3D astronomy modeling program.
Over ten years after playing Prime Minister Allison Colby in First World (2007), Lindy Nettleton reprised the character in the prequel First Signal. Michael Anthony Coppola who played a secret service agent in First World, returned to First Signal as Senator Hadrian.
The McAuliffe-Shepard Discovery Center in Concord, New Hampshire served as Chièvres Air Base (exterior and interior). The windowless function room at the Discovery Center was the location for the conference room scenes that take place in a "bunker" under a hotel complex.
Mark Lund met Patience McStravick when they were working as actors in the mock trial program at the Naval Justice School in Newport, Rhode Island. After discussing ideas for a story that takes place largely in one room, Lund revisited his notes from First World (2007) and came up with the prequel First Signal.
The secret meeting between the President of the United States Wendy Hartman, the Prime Minister of the United Kingdom Lindy Nettleton and the President of the Russian Federation Yefim Somin is reflective of the Yalta Conference that took place towards the end of World War II in the Crimea. Part of the First Signal story goes back to World War II. First Signal also features a moment of tension between Russia and the United States when they clash over the Crimea. First Signal takes place in 2014 when Russia had just annexed the Crimea.