He was eldest son of Alexander Napier, sixth of Merchiston, who was killed at the
battle of Pinkie in 1547. His mother was Annabella, youngest daughter of Sir Duncan Campbell of Glenurchy. His paternal grandfather was Alexander Napier, 5th Laird of Merchiston, fifth of Merchiston, who was killed at the
battle of Flodden in 1513. Archibald was
infeft in the barony of Edenbellie as heir to his father on 8 November 1548, a royal dispensation enabling him, though a minor, to feudalise his right to his paternal barony in contemplation of his marriage with Janet Bothwell, which took place about 1549. Napier began to clear his property of encumbrances. On 1 June 1555 he redeemed his lands of Gartnes,
Stirlingshire, and others from Duncan Forester, and on 14 June 1558 he obtained a precept of
sasine for infefting him in the lands of Blairwaddis,
Isle of Inchcolm. In 1565 he received the order of knighthood. According to
Claude Nau, Napier had the reputation of being a wizard or magician and made bets that
Mary, Queen of Scots would escape from
Lochleven Castle. He sided with her when she gained her freedom. In 1569,
William Stewart of Luthrie was accused of witchcraft and conspiracy against
Regent Moray. He was said to have held meetings in the loft or upper chamber of
Merchiston Tower with Napier to conjure a spirit called "Obirion". Stewart also made an invocation to summon Obirion in the "yaird" or garden at Merchiston. During the siege of
Edinburgh Castle, held by
Kirkcaldy of Grange for the queen, he was required on 1 May 1572 to deliver up his house of Merchiston to the king's party, who placed in it a company of soldiers to prevent victuals being carried past it to the castle. On this account the defenders of the castle made an attempt to burn it, which was unsuccessful. ==Mining and the mint==