Sometimes styled ‘clerk’ or ‘Master Petworth’, William was evidently a man of some education. He took his surname from his birthplace in Sussex but he had formed a connexion with Colchester by the mid 1430s. In May 1435 John Saveyn* and another burgess acknowledged in the borough court that they owed him 60 marks, and he was admitted a freeman of the town in October 1436.
Soon after becoming a freeman, Petworth began acting as a feoffee, witness and arbiter for other burgesses,
It would appear that Petworth did not hold further office in Colchester after completing his second term as bailiff in 1460. Still alive in January 1461, when amerced for keeping a ruined gutter in a lane next to his house,
