In 1541 he received from the Grand Master the ancianitas (right of expectancy) to the Preceptory and, following the death of Sir Walter Lindsay, succeeded him as Preceptor, authorized by a bull of 2 April 1547.
On 24 January 1563, Sandilands appeared before Mary, Queen of Scots, at the behest of the Grand Preceptory, to surrender the lands and possessions of the Order, together with the title of Lord St. John, which he had held as Preceptor.
In April 1573, James Sandilands was summoned by the Lord Advocate to be questioned by the Privy Council of Scotland and Regent Morton about the possessions of Mary, Queen of Scots.
Sandilands related that Mary's valet, Servais de Condé had asked him to look after some belongings of the queen's uncle, Francis, the Grand Prior (1534-1563).
[4] Regent Moray mentioned this incident in a letter to Elizabeth I on 11 March 1569, as the "taking the Lord of St John, a peaceable and honest gentleman forth of his own house, who also was spoiled of all his goods".
[5] The royal possessions at Hamilton were returned to Holyrood Abbey by the forces of the young James VI and I. Sandilands said that Servais de Condé received, "so many books, and such moveables, which were all dispersed, dimembered, and spoilt by the soldiers, and [by] harling them on sleds through the foul moors and taking no accompt of the keeping of them when they were in Hamilton".
Janet Murray died on 29 November 1596, which some historical books have given as an alternative date of James' death.