The Xbox 360 introduced backward compatibility with selected original Xbox games at launch.
Microsoft included backward compatibility support when Xbox 360 launched in 2005, allowing certain original Xbox games to run on the newer console. Compatibility was not universal: supported titles required an official software update and, in many cases, the original game disc. The list grew over time but remained selective.
This feature helped players move from the first Xbox to the Xbox 360 without immediately abandoning their existing game libraries. It also demonstrated the importance Microsoft placed on digital system software and emulation during the transition between console generations.
Later Xbox consoles expanded the idea. Xbox One supported selected Xbox and Xbox 360 games, while Xbox Series X and Series S continued compatibility with many titles. A common mix-up is assuming every original Xbox game worked on Xbox 360; compatibility depended on Microsoft’s published list and technical testing.