In one implementation, a stair installation bracket for installing staircases in stairwells is provided. The bracket includes a bracket assembly configured to anchor to a wall of a stairwell, a hanger tool removably connected to the bracket assembly, and a positioning bolt for positioning a staircase relative to the wall. A method of installing a staircase using the bracket assembly includes positioning the staircase on tabs of one or more bracket assemblies, rotating the positioning bolt to vertically positioning the staircase relative to pilot holes of the bracket assembly, anchoring the staircase to the bracket assembly, and removing the hanger tool from the bracket assembly.