The writers saw the B-story of this episode as an important indication of how DS9's Worf was going to be different from TNG's Worf. As Ronald D. Moore explains, "He used to be a cop, more or less, on the USS Enterprise-D, but it's not going to be like that anymore. We wanted to keep emphasizing, 'this is not TNG. The station doesn't work like the Enterprise. Worf is going to have some troubles fitting in, but he's going to learn.'"
This episode came from two separate story pitches by two different writers. The first, from Nicholas Corea, was based around the story of a group of Jem'Hadar who were trying to free themselves from their addiction to ketracel-white, the first time the name is used. Previously, it had been described as a "missing enzyme" in "The Abandoned" and simply as a drug to which the Jem'Hadar are addicted in "The Die is Cast". The second, from Lisa Klink, was about O'Brien and Bashir taking opposing sides in a conflict on an alien world - O'Brien sided with the natives, Bashir with the non-natives. The producers liked the idea of Klink's concept, putting O'Brien and Bashir on diametrically opposed sides, but they felt that the details weren't quite right and they got Klink to re-pitch the story several times with different plot elements in place. Producers referred to her story as their The Bridge on the River Kwai episode, and they likened Bashir to Col. Nicholson, the character in that film played by Alec Guinness, who effectively helps the 'enemy'. The problem with Klink's story was that producers couldn't decide exactly what it was that Bashir was trying to do for the enemy, what was causing the conflict between himself and O'Brien - what was the 'Bridge'? Eventually, it was René Echevarria who suggested putting Klink's story together with Corea's, thus providing the Bridge - Bashir was trying to help the Jem'Hadar beat their addiction, and O'Brien was against this idea.
Since "Shadowplay", O'Brien's rank has been referred to as simply chief petty officer, as identified by Goran'agar, rather than the prior senior chief petty officer.
Robert Foxworth auditioned for the role of Goran'Agar, but the producers were so impressed with his performance that they decided to save him for a more substantial role in the future. They went on to cast him as Admiral Leyton in the two-parter "Homefront" and "Paradise Lost".
In an interview with the official Star Trek website in 2011, director Rene Auberjonois thought this episode was the one that stood out the most for him out of the eight he directed throughout Deep Space Nine.