He is playable from the start. You don't have to unlock him.
You can't unlock Louie the closest you can get to him is Olimar you might be able to get him with a hack but I don't know if it's possible
Olimar
No, just Olimar.
olimar
You have to be olimar. Just press B.
you can't unlock him in super brawl summer you only unlock him in super fall brawl
you can't unlock him in super brawl summer you only unlock him in super fall brawl
He can carry up to 5
You cannot unlock him in jingle brawl, you can only unlock him in super fall brawl
how to unlock skipper in super fall brawl and sheen
If you're thinking of the Sonic Riders character, you cannot unlock him in Brawl.
People say it's either Ice Climbers or Olimar or R.O.B.