Xbox 360 has backward compatibility with the number of supported Xbox games depending on the region you are in. Check this list page for original Xbox games that you can play on your Xbox 360 console.
An internal official Xbox hard drive is required to play emulated Xbox games. You can not play Xbox games without a hard drive that doesn’t have enough space. For those with Xbox 360 S or E models that came only with 4GB of built-in hard drive space, you can easily upgrade with an internal official hard drive on Ebay for around $35-$40. These 360 internal drives are not as expensive as they were when it first came out.
Once you have enough hard drive space, start up your 360 and make sure you are logged into your Xbox Live account. Xbox Live accounts are free to sign up. Your console will automatically download and install the necessary software to play original Xbox games. That’s it! Simple enough. The hard part is finding those classic Xbox 360 compatible games in the secondary market and not pay an arm and a leg for the ones you like.
Playing original Xbox games on your Xbox 360 console has never been easier. Games like Star Wars Battlefront II (2005 version) never gets old.