Fred's full name is Frederick Hobart Mertz.

Fred was raised on a farm.

Fred is the landlord of their building.

Fred's last vaudeville playing was in 1925.

Fred played a frog in the school production, The Enchanted Forest.

NitAlert
In "The Diet" Fred has a dog, Butch. But we never see the dog again! In fact, later in the series, Little Ricky wants to keep a dog, but Fred says dogs aren't allowed in the building.