Gesualdo is a custodian at Hamlin, Hamlin & McGill.
When Jimmy arrives at HHM, Gesualdo informs him that Chuck isn't at the office. Jimmy makes an excuse to be allowed entry by telling him that he needs to get Chuck's ink blotter from his office. ("Gloves Off")
Jimmy returns to HHM the following day and is allowed in by Gesualdo. ("Rebecca")