Andy seems to be very quiet and reserved, which serves his role as the business manager of the restaurant. He is actually extremely crafty and manipulative. Unbeknownst to his brother and sister, Andy has been talking with Mister Burke about his insidious plan to blow up Megaton so he can move the restaurant to a better, safer and more lucrative location.
In Colin Moriarty's private terminal, Colin remarks about Andy, "This guy is a real piece of work. Opening a fucking bar in my town? What a jackass. I swear, he's up to something. I'm going to have to think of a way to reduce his business a little. For now at least I still got my secret weapon...Nova: best refreshment in town."
Andy also tends to be very aggressive towards the Lone Wanderer, even if they stop Andy's brother from using chems/drugs.
He also says that Colin Moriarty "pisses in his still", showing the rivalry between the bar and the saloon.
Andy will make reference to being in the Brass Lantern even if he isn't actually in it at the time.
Convincing Leo to quit using drugs leads Andy to confront the Lone Wanderer, offering his thanks and saying, "My little brother means the world to me." However, Leo is 25, and Andy is 23, making Andy the little brother.