Douglas was the second son of Archibald Douglas, 5th Earl of Angus, and his wife Elizabeth, daughter of Robert Boyd, 1st Lord Boyd.^[1][2] He obtained the lands of Glenbervie by his marriage and was thereafter styled Douglas of Glenbervie.^[2]

In 1493 and 1509 Douglas was in possession of charters of the lands of Grenane, in Ayrshire. The lands of Braidwood, in Lanarkshire, were confirmed to him in 1510.^[2]

William Douglas was knighted before 1511,^{[citation needed]} and was slain on 9 September 1513 at the Battle of Flodden.^[3]

Douglas was pledged in marriage, by contract, in 1492, to Elizabeth, daughter and co-heir of the later James Auchinleck of that Ilk, by which contract he received a grant of the wardship of Auchinleck's estates. They had a son Sir Archibald Douglas of Glenbervie.^[3]

Elizabeth Douglas survived her husband and entered the convent of St. Catherine of Siena, on the Burgh Muir of Edinburgh.^{[citation needed]} This convent was to give its name to the Sciennes area of the city.

• Burke, John; Burke, John Bernard (1848), The royal families of England, Scotland, and Wales: with their descendants, sovereigns and subjects, vol. 1, London: E. Churton, pedigree CLXXXV
• Douglas, Sir Robert; et al. (1798), The Baronage of Scotland, Edinburgh, pp. 18, 19
•   This article incorporates text from this source, which is in the public domain: Balfour, Paul, James (1904). The Scots Peerage; founded on Wood's edition of Sir Robert Douglas's peerage of Scotland; containing an historical and genealogical account of the nobility of that kingdom. Vol. 5. Edinburgh: D. Douglas. pp. 145, 146.{{cite book}}: CS1 maint: multiple names: authors list (link)

• Burke, John; Burke, John Bernard (1851), The royal families of England, Scotland, and Wales: with their descendants, sovereigns and subjects, vol. 2, London: E. Churton, pedigree CCVIII
• Mackenzie, A.M. (1935), The Rise of the Stewarts, London{{citation}}: CS1 maint: location missing publisher (link)