After graduating, Sainsbury formed Fingerprints and Teeth Productions, a theatre company for which he wrote and produced several plays becoming a ‘powerhouse of creativity’, writing, performing and directing countless plays, as well as writing for television.
Sainsbury has won Playmarket’s Young Playwright of the Year four times and has been a finalist for the Bruce Mason Award and the Playmarket New Play Award. His play The Canary also won Playmarket’s 2010 Special Prize for an Auckland Playwright. Several plays, including The Christmas Monologues, . . . and then you die and A Simple Procedure have had seasons in London and Australia. He is the co-writer of the television series Super City for which he has won a SWANZ for Best Comedy Script.