Removable door jamb assembly guard, guarded jamb assembly, and methods of controlling a doorway. The guard preferably covers the full length of the jamb assembly, and the full width of the jamb assembly between an outer trim element and the door-arresting surface. The guard has a central section, a door leg section, an outer leg section disposed outwardly of the central section, and optionally a transition section between the central section and the outer leg section. Preferred embodiments of the guard can be installed on a jamb assembly while a conventional door slab is mounted to the jamb assembly, and the door slab can be closed and opened without the guard interfering with such operation of the door slab.