Surveillance cameras show a brazen man climbing onto a second-story deck, and entering the building through a window.
The man took the money from a locked area as actors performed, and was also seen helping himself to beer.
The stolen cash was supposed to be used to pay actors in the play, as well as the venue.
The burglar was wearing a black shirt with a distinctive red pattern on the back, cargo shorts, and flip-flops. He has dark hair, and wears glasses.
Anyone who recognizes the man seen in surveillance photos is asked to call Seattle police.