The building has undergone several renovations and alterations to its interior. In the 1960s and 1970s, before the post office vacated the site, original finishes in some portions of the interior were covered or removed. Some office spaces were finished with modern materials and part of the main post office area was sheathed in drywall in 1975. However, many public spaces remain intact. The south lobby at Grant Street is two stories. Walls are covered with pink Alabama marble and a marble dentil course encircles the room. Floors are covered with gray marble, while decorative coffered plaster ceilings top the space. Mouldings surrounding the bronze and glass doors contain ornate rope and garland designs. Original custom glass light fixtures remain in the lobby.
