It is thought that he was a member of Lord Seton's party, a small select group who were entrusted to journey to England in 1575, ostensibly to pay homage to Queen Elizabeth, but in reality to smuggle letters to the imprisoned Mary Queen of Scots from the Scottish Regent, James Douglas, 4th Earl of Morton.
He bought sugar confections called "scrotchets and confitures" in Copenhagen for the return journey, sweets which were thought to help sea sickness.
[6] In an era of vacillating political loyalty, he was suspected of involvement in the December 1591 raid on Holyroodhouse by the Earl of Bothwell.
[12] Naysmyth and Martin Schöner, Anne of Denmark's physician, attended the infant Princess Margaret at Linlithgow Palace in 1600, and the births of Prince Charles and Prince Robert at Dunfermline Palace with the midwife Jonet Kinloch and the apothecary Alexander Barclay.
Presumably, as a result of Primrose’s patronage, Naysmith was made a surgeon to the king, and he too moved with the court to London.
Naysmith died in London and was buried in Greyfriars churchyard in Edinburgh where an elaborate monument marks his grave.
[1][14] The inscription in Latin is now almost obliterated but has been translated as follows; Here lies John Nasmyth, of the family of Posso, an honourable family of Tweedale, a citizen of Edinburgh, chief surgeon to his most Serene Majesty and to the King of France's troop of guards from Scotland - having excellently performed all the duties of a godly life; who dying at London to the grief of both nations, in the exercise of office with his Majesty, ordered his body to be conveyed hither (such was his love to his country), to be buried in this dormitory; acquiting himself to his King, his country and his friends by the utmost of his power and duty.