There are multiple ways to unlock the characters of Super Smash Bros. Ultimate by playing the different game modes that it offers. Through the game’s World of Light, Versus, and Classic Modes you can unlock Little Mac in Smash Bros. Ultimate.
Little Mac can be unlocked quickly by completing just a few rounds of Classic Mode, but he is unlocked in Mario’s character unlock route in Classic Mode. To unlock Little Mac in Classic Mode you will need to have beaten classic mode with Mario, Sonic, and Bayonetta. The next time you play with Mario, Sonic, or Bayonetta and complete the Classic Mode you will be able to challenge Little Mac for the character unlock.
The fastest way to unlock Little Mac in Super Smash Bros Ultimate
The quickest way to unlock Little Mac in Super Smash Bros. Ultimate is definitely to go about it by beating Classic Mode with Mario, Sonic, or Bayonetta as described above. Otherwise he’s one of the later unlocks in World of Light mode and in versus mode he will also take a little bit of grinding to unlock.
Simply head into Classic Mode, play on any difficulty, and beat the six stages, bonus level, and boss battle. Once you’ve completed Classic Mode with Mario, Sonic, or Bayonetta you will then see the New Challenger Screen which starts the fight with Little Mac.
You will need to beat Little Mac in a one on one match to add him to your roster. Once you do you will have permanently unlocked Little Mac in Super Smash Bros. Ultimate. However, if you lose to Little Mac in the one versus one match he will not be unlockable via this method for a little while. You can still unlock other characters in Mario’s Classic Mode Route though. If you lose to Little Mac, the character that you can unlock leapfrogs Little Mac in the case of Mario, Sonic, or Bayonetta it would be Ike.
After a bit of time this rematch will be available in the Games & More section of the main menu. If you want to go back and unlock Little Mac but you lost the first time, head to the Challenger’s Approach and then fight them again to unlock.
Mario Route Classic Mode
All of the characters in Mario’s Route can be unlocked with the ones before it in Classic Mode. Meaning Mario will unlock Sonic, Mario and Sonic can unlock Bayonetta. Mario, Sonic, or Bayonetta can unlock Little Mac, and so on. If you fail to beat one of the challengers to unlock them, it will then skip to the next challenger. The one that you lost to will reappear later.
Mario > Sonic > Bayonetta > Little Mac > Ike > Luigi > Roy > Dr. Mario > Olimar.