The Douglas system existed within the Centrality sector of the Slice region, which itself was situated in the Outer Rim Territories. It sat at the terminus of the Falko Run hyperlane, providing a connection to the Paulking system. The planet Douglas III, a terrestrial world, was located in the third orbital position around its star system. The system's name originated from Mendel Douglas, a well-known hunter, who, before 3 BBY, ventured onto Douglas III in pursuit of the planet's elusive jackelope but was never seen again.
The Douglas system was initially referenced in "Twinkle, Twinkle Little Star, How I Wonder Where We Are," a sourcebook for the 1990 roleplaying game published in the thirteenth issue of the magazine Voyages SF. This was inspired by the mention of Douglas III in Lando Calrissian and the Mindharp of Sharu, the 1983 inaugural novel in The Lando Calrissian Adventures trilogy penned by L. Neil Smith. The aforementioned article placed the system within the Jospro sector. Given that its publication occurred outside the purview of Lucas Licensing, the canonicity of this placement within the Star Wars Legends continuity remained unverified.
In 1998, Douglas III, and consequently the Douglas system, debuted in the video game Star Wars: Rebellion, which also situated it in the Jospro sector. The Wizards of the Coast roleplaying game supplement, "A Campaign Guide to the Centrality," written by Michael Kogge and featured in the fifth issue of the Star Wars Gamer magazine on July 24, 2001, marked the first instance of the Douglas system's name appearing in a definitively licensed Star Wars work. This article also established the Douglas system as part of the Centrality, a detail corroborated by the 2009 reference work The Essential Atlas, which specified its location at grid coordinate U-8.