Brendan Greene, better known by his online handle PlayerUnknown, is the lead designer and director of PlayerUnknown's Battlegrounds. He had previously worked on other games using the 2000 film Battle Royale for inspiration, and expanded into a standalone game under Greene's creative direction.
His most notable and popular creation before the game was the ArmA 2 mod DayZ: Battle Royale, an offshoot of popular mod DayZ, and inspired by the film mentioned previously. At the time he created DayZ: Battle Royale around 2013, Irish-born Greene had been living in Brazil for for a few years as a photographer, graphic designer, and web designer. He typically played video games such as Delta Force: Black Hawk Down and America's Army. The DayZ mod caught his interest, both as a realistic military simulation and its open-ended gameplay, and started playing around with a custom server, learning programming as he went along. Greene had been inspired to create the Battle Royale mod as he found that in most multiplayer first-person shooter games, there was too much repetition, as maps were small and easy to memorize. He wanted to create something with more random aspects so that players would not know what to expect, creating a high degree of replayability; this was done by creating vastly larger maps that could not be easily memorized, and using random item placement across it. Greene was also inspired by an online competition for DayZ called Survivor GameZ, which featured a number of Twitch and YouTube streamers fighting until only a few were left; as he was not a streamer himself, Greene wanted to create a similar game mode that anyone could play. His initial efforts on this mod were more inspired by The Hunger Games novels, where players would try to vie for stockpiles of weapons at a central location, but moved away from this partially to give players a better chance at survival by spreading weapons around, and also to avoid copyright issues with the novels. In taking inspiration from the Battle Royale film, Greene had wanted to use safe square areas, but his inexperience in coding led him to use circular safe areas instead, which persisted to Battlegrounds.
When DayZ became its own standalone title, interest in his ArmA 2 version of the Battle Royale mod trailed off, and Greene transitioned development of the mod to ArmA 3. Sony Online Entertainment (now the Daybreak Game Company) had become interested in Greene's work, and brought him on as a consultant to develop on H1Z1, licensing the Battle Royale idea from him. In February 2016, Sony Online split H1Z1 into two seperate games, the survival mode H1Z1: Just Survive, and the battle royale-like H1Z1: King of the Hill, around the same time that Greene's consultation period was over.