During the rehearsal period, the Assistant Stage Manager acts as the Stage Manager's assistant helping set up and strike rehearsal furniture and props, taking down Line Notes, tracking props, prompting actors, etc. as per the SM's instructions.

During Technical and Dress Rehearsals, and performances, the ASM is responsible for the smooth and efficient running of the backstage area. The ASM is stationed backstage and supervises and/or participates in all scenery changes and any props and/or costume changes as needed.

During performance, the ASM is responsible for overseeing the backstage Run Crew members.

The ASM/Deck Captain may be responsible for handing out props directly to actors going onstage and collecting them from actors leaving the stage. These duties may be delegated to Run Crew members.

During scene changes, the ASM is the last crew member to leave the stage and does a final check to insure all props and scenery have been properly set or struck.

The ASM is responsible for insuring that all electronics (cell phones, laptops, iPods, Blackberries, etc. etc. etc.) are turned completely off backstage.

The ASM is responsible for insuring that there are no non-Cast or Crew members loitering backstage during technical rehearsals, dress rehearsals, and performances.

The ASM is responsible for the clean and orderly upkeep of the entire backstage area.

The ASM is also responsible for filling in for the Stage Manager if the Stage Manager is absent.