Appearance
Just like Mike, Jeremy is never seen, as the player is in first-person view of him the whole entire game. A difference about them is when Jeremy is killed, the player is still in first-person of him when the game over screen is displayed, unlike Mike, where the player is in third-person view of him, dead inside a Freddy Fazbear suit.
Personality
Similar to Mike, it's unknown of his behavior, but seems to be very focused and competent, due to the fact he can hold off all ten (eleven if you count Golden Freddy) of the killer animatronics at any time. Unlike Mike, however, Jeremy seems to be somewhat scared due to his heavy breathing when wearing the Freddy Fazbear Mask.