We don’t know much about Hezekiah save a brief mention of him in Josephus and these coins. It’s generally believed that he was either the last or one of the last satraps of Yehud.
Regardless, we do know he was the governor of the region because some of the coins tell us exactly that. The primary debate is when. Most believe shortly before the arrival of Alexander – and perhaps Alexander replaced him – while others say it was during the Ptolemaic times.