Instructions
Win 450 Battles
Start "Super Smash Bros. Brawl" and select "Vs." mode from the "Start" menu. Wolf can be unlocked by winning 450 battles in any mode, although it is easiest to win these battles by modifying your opponent's stats in "Vs." mode.
Select "Special Brawl" from the "Vs" mode menu. Select "Stamina" and set it to "Flower." Set your opponent's health to one and your health to any number higher than one.
Start the battle. The battle will begin with your opponent immediately dying because of the health drain caused by setting his stamina to "Flower." Do this 450 times to unlock Wolf.
Boss Battle Mode
Unlock "Boss Battle." "Boss Battle Mode" is unlocked by beating both "Classic" and "Subspace Emissary" mode on any difficulty.
Beat "Boss Battle" mode using Fox on any difficulty to unlock Wolf.
Beat "Boss Battle" mode using Falco on any difficulty to unlock Wolf.
Subspace Emissary
Beat "Subspace Emissary" using any character on any difficulty. You will not be able to find and unlock Wolf in "Subspace Emissary" on your first play-through.
Select the level "Ruins" from "Subspace Emissary." Fight your way through the level until you reach the elevator with the purple spikes.
Ride the elevator with the purple spikes all the way down until you see a red door. Enter the red door and you will find Wolf, who will then teleport you to his ship for a one-on-one battle. Defeat Wolf in this battle to unlock him.