Professor Oak 

Hometown:  Pallet town

League Status:  Professor of Pokémon at Pallet

Hair:  Grey

Background
Professor Oak was known to be a very famous trainer his day.  However, as he got older, we see that he became a Pokémon professor.  Professor Oak is the one who handed out a Pokémon to Gary (we still don't know who it is, but it might be the Eevee that Gary has since it would follow along the storyline of Yellow) and handed out Pikachu to Ash.  Professor Oak also keeps all of the Pokémon that the trainers of Pallet catch and takes good care of them, too.  Professor Oak truly knows a lot about Pokémon and is normally the one to give advice about the area that Ash is in.

Personality
Professor Oak has a kind and outgoing personality.  Whenever Ash needs advice about the area that he's in, Professor Oak is always the one to call and make sure that Ash stays safe in that town.  He also cares for the Pokémon very well and makes sure that each Pokémon gets some time outside of it's pokeball.