At its launch in November 2013, the Xbox One did not have native backward compatibility with original Xbox or Xbox 360 games. Xbox Live director of programming Larry "Major Nelson" Hryb suggested users could use the HDMI-in port on the console to pass an Xbox 360 or any other device with HDMI output through Xbox One. Senior project management and planning director Albert Penello explained that Microsoft was considering a cloud gaming platform to enable backward compatibility, but he felt it would be "problematic" due to varying internet connection qualities.
During Microsoft's E3 2015 press conference on June 15, 2015, Microsoft announced plans to introduce Xbox 360 backward compatibility on the Xbox One at no additional cost. Supported Xbox 360 games will run within an emulator and have access to certain Xbox One features, such as recording and broadcasting gameplay. Games do not run directly from discs. A repackaged form of the game is downloaded automatically when a supported game is inserted, while digitally-purchased games will automatically appear for download in the user's library once available. As with Xbox One titles, if the game is installed using physical media, the disc is still required for validation purposes.

Not all Xbox 360 games are supported; 104 Xbox 360 games were available for the feature's public launch on November 12, 2015, with Xbox One preview program members getting early access. Launch games included the Gears of War series, Mass Effect, Borderlands, Mirror's Edge, Assassin's Creed II, and more. Microsoft stated that publishers will only need to provide permission to the company to allow the repackaging, and they expect the list to grow significantly over time. Unlike the emulation of original Xbox games on the Xbox 360, the Xbox One does not require game modification, since it emulates an exact replica of its predecessor's environment – both hardware and software operating systems. The downloaded game is a repackaged version of the original that identifies itself as an Xbox One title to the console. At Gamescom, Microsoft revealed it has plans to ensure "all future Xbox 360 Games with Gold titles will be playable on Xbox One." On December 17, 2015, Microsoft made another sixteen Xbox 360 games compatible with Xbox One, including titles such as Halo: Reach, Fable III, and Deus Ex: Human Revolution. On January 21, 2016, Microsoft made another ten Xbox 360 games compatible, including The Witcher 2: Assassins of Kings and Counter-Strike: Global Offensive. On May 13, 2016, Microsoft made Xbox 360 titles with multiple discs compatible, starting with Deus Ex: Human Revolution Director's Cut. In January 2016, Microsoft announced that future titles would be added as they became available, instead of waiting until a specific day each month.
During Microsoft's E3 2017 press conference on June 11, 2017, Microsoft announced that roughly 50% of Xbox One users had played an Xbox 360 game on Xbox One through the system's backward-compatibility feature. Based on popular demand, Phil Spencer, Microsoft's Head of Xbox, announced that Xbox One consoles would be able to play 13 games made for the original Xbox console, first released in 2001. The compatibility works on all consoles in the Xbox One family, including the Xbox One X, and was made available as a free update in the fall of 2017.

The functionality is similar to that for back-compatibility with Xbox 360 games…

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