John Croker, born in Saxony and known in his youth as Johann Crocker, was a master jeweller who migrated to London, where he became a medallist and engraved dies for English and later British coins and medals.
For most of his adult life Croker worked in England, serving provincial mints as well as that at the Tower of London. For some seven years he engraved the die stamps for the coins of King William III and Queen Anne before becoming Chief Engraver to the Royal Mint, a position he held from 1705 until his death. He worked closely with the head of the Mint, the famous scientist Isaac Newton.