Diablo 2 Resurrected: Resurrected's development began around 2019, as a joint effort between Blizzard's Diablo team (Team 3) and Vicarious Visions, at the time a subsidiary under Blizzard's corporate sibling Activision. According to Blizzard's president J. Allen Brack, Vicarious Visions was responsible for handling the front-end and 3D client while Blizzard handled the back-end server and Battle.net integration aspects of the remaster. About a month before the February 2021 announcement of the game, Activision announced that Vicarious Visions had been transferred and moved into Blizzard's corporate structure. Brack said this move was due to Vicarious having detailed knowledge of the Diablo series by this point, so that they could not only continue to provide support for Resurrected but also for Diablo IV and other Blizzard properties.

During a 2019 media event, Max Schaefer, Erich Schaefer, and David Brevik stated they had been unsure if a remaster of Diablo II was possible due to a near-release loss of much of the game's source code and assets from corruption in their backup system. They were able to recover most of the code and assets through copies that employees of Blizzard North had taken home with them or other means, but the Schaefers felt there were still too many pieces missing to fully remaster the game. However, according to Blizzard's current Diablo lead Rod Fergusson and principal designer Rob Gallerani, the missing data was not as bad as the Schaefers had implied. Their team scoured through other sources at Blizzard, such as through marketing material, to find additional resources to fill in the gaps. After assessing what was missing Blizzard decided they had enough to proceed with the remaster, with capabilities to recreate any missing assets and redraw the existing assets in higher definition with help of the original artists and animators from the game.

The remaster's design philosophy required the game to be identical to what legacy players remembered. While the developers did not make even minor changes to core gameplay, they upgraded the game's visuals, modeling its remastered graphics on art from the original game. The remaster includes some small usability changes like the Shared Stash and automatic gold pickup. Some new conveniences, like the latter, can be toggled to the user's playstyle preference.

The title was announced in the opening ceremony of the developer's February 2021 annual convention. Its development had been an open secret, having been leaked during Blizzard's acquisition of developer Vicarious Visions the month prior. A single-player beta period will precede the release. Unlike Warcraft III: Reforged, the prior remaster of Warcraft III which was met with criticisms from journalists and players, Diablo II: Resurrected will be a separate release from the existing Diablo II on Battle.net.Brack said that they had learned various lessons from how they approached Warcraft III: Reforged from fan reactions that they will avoid with Resurrected.

Diablo II: Resurrected is slated for release on September 23, 2021, for Nintendo Switch, PlayStation 4, PlayStation 5, Windows, Xbox One, and Xbox Series X platforms.Prior to release, the game will have two development tests open to players: The single-player alpha ran in April, followed by an open multiplayer beta in August, with those who pre-ordered the game also gaining early access on supporting platforms. Blizzard made multiple tweaks and additions based on community feedback during the technical alpha, including touch-ups of visual effects, revised item icons, interface usability toggles, and new features such as an in-game clock and extra player item storage.