The Second Assistant Director assists the First AD by placing extras in scenes, giving them directions, and helping the First AD in whatever is needed to be done. They also check the extras in, give out the vouchers and collect the vouchers at the end of the day. On big calls, there may also be one or more people referred to as a "second second". The more extras there are, the more people are needed to supervise the extras. Although sometimes one is referred to as a Second Second AD, more often those helping with the extras are the Production Assistants, or PAs.

Often two or three on a set, they handle checking in the talent, insuring proper paperwork is filed, and distribute script revisions. Actors check in with the 2nd A.D. upon arrival on the set.

Assistant to the assistant director whose duties include overseeing the movements of the cast, and preparing call sheets.