Jeremy Fitzgerald is the security guard in FNAF 2, as shown by the paycheck you receive when beating Night 5. Much like Mike Schmidt from the first game, he is the main protagonist and the player's character in the game. There are no identified facial details than can be seen on Mr. Fitzgerald, because, unlike the death screen in FNAF 1, where you can see Mike's blue eyes coming out of the Freddy Fazbear suit, Jeremy is still in first person view in the game over screen occurs, so no facial details can be seen.
Jeremy continues to work at the pizzeria as Night Guard, despite the obvious danger, nearly dying several times and the low wage. Jeremy is a very mysterious protagonist in the FNAF series.
Jeremy appears to have Nightmares everytime he goes away from work, from the first-person Freddy moments are titled "Dreams".