Once the first tournament is out of the way you'll make the jump onto the rankings ladder. As usual, combinations and keeping your guard up provide the route to success. This shouldn't pose too much of a threat, as simply landing blows will get you a decent score in this one.
Upon starting your career you'll be placed in an amateur tournament. Either way, you'll start with limited XP and a fighter who needs to be developed. If you choose a real-life professional, you can edit their style and appearance before starting. The first major decision you need to make is whether you want to create a boxer or take an existing pro on an alternate journey through their career.
Fights need to be scheduled, training participated in, and ultimately, you need to squash as many higher ranked boxers as possible. Stripped away from drama of Champion Mode, you're tasked with taking a created or real professional to the top of the rankings. Included annually in Fight Night games, the Legacy Mode will be familiar to anyone who's played before.