Political career
Following the restoration, William Bruce was appointed Clerk to the Bills in 1660, and Clerk of Supply to the Lords in Council in 1665. Both were lucrative positions, involving collection of fees, from Parliament in the first case, and from petitioners to the Court of Session in the latter. Meanwhile, Sir Robert Moray had established himself as a courtier and scientist at Whitehall, London, and employed Bruce as a trusted messenger between Whitehall and the Duke of Lauderdale, Secretary for Scotland.
Moray later served on the Treasury Commission for Scotland, as did Alexander Bruce, now Earl of Kincardine. Bruce reported to this commission as a revenue collector, and benefited from the patronage of its members. The Commission had responsibility for the King's Works, and in 1667 Bruce was appointed Superintendent and Overseer of the Royal Palaces in Scotland. Four years later he was made Surveyor General of the King's Works in Scotland, with a salary of £3600 Scots (£300 Sterling, or £ 57,000 in 2025), for the purpose of rebuilding Holyroodhouse. In March 1671, Bruce was part of a syndicate which bought the rights to collect taxes over a five-year period, paying £26,000 Sterling (£ 5 million in 2025) for the privilege. As such, it would appear that Bruce was not only the architect of Holyroodhouse, but one of the principal financiers of the £21,000 project.
As a key figure of the Restoration administration, William Bruce became close to other Stuart loyalists, who included such powerful patrons as the Duke of Lauderdale, Lord Haltoun, and the Earl of Rothes. In 1667, he undertook his first building work for Lord Rothes, overseeing the extensions to Leslie House, and later worked on several of Lauderdale's properties, concurrently with Holyroodhouse. In 1668 he was created a Baronet of Nova Scotia.
From 1669 to 1674 Bruce sat in the Scottish Parliament as shire commissioner for Fife, and from 1681 to 1682 as a shire commissioner for Kinross. From April 1685 to May 1686 he reached the peak of his political career, as a member of the Privy Council of Scotland. But, in 1674, he became embroiled in factional rivalry between his patron Lauderdale, and his rivals William Douglas, Duke of Hamilton and John Hay, 2nd Earl of Tweeddale. His actions, which apparently included passing information to Hamilton, invoked the fury of Elizabeth Maitland, Duchess of Lauderdale, who tried to persuade her husband to deprive Bruce of his offices. Bruce survived, although his relationship with his patron was damaged. Lauderdale described him as "the bitterest factionalist partie man of his quality in all Scotland". This breakdown resulted in Bruce's eventual dismissal as Surveyor General of the King's Works, on the false pretext that Holyroodhouse was finished.
Bruce's earnings from his offices had made him a wealthy man, even by the standards of his patrons. This wealth allowed him to purchase the Balcaskie estate in 1665, and to extend the house and gardens. In 1675 he purchased the larger estate of Loch Leven, Kinross, from William Douglas, 9th Earl of Morton, which brought him the hereditary sheriffdom of Kinross-shire. In the late 1670s Bruce took on his first architectural projects for entirely new houses.
Following the accession of James VII in 1685, Bruce gradually fell from favour, and was distrusted by the new regime. After the Revolution of 1688, and the accession of William of Orange as king, he was once again at odds with his Protestant rulers, and he refused to take up his seat in Parliament. As a staunch Episcopalian, Bruce was considered a potential Jacobite threat. In 1693 he was briefly imprisoned in Stirling Castle for refusing to appear before the Privy Council. He was incarcerated again at Stirling in 1694, and from 1696 in Edinburgh Castle. Bruce was expelled from parliament in 1702, his seat passing to his son John Bruce. Despite these imprisonments, he continued his architectural work, indeed the 1690s and 1700s were his most prolific years. Bruce was imprisoned at Edinburgh Castle again in 1708 and was only released a short time before his death, at the beginning of 1710.
He was buried in the family mausoleum at Kinross Kirk. The ruins of the church still stand beside Kinross House, the mausoleum remains intact in the churchyard. Dating from 1675 it is probably by William Bruce in design, initially to house his parents.
Bruce's surviving account books show purchases of books on music, painting and horticulture, as well as numerous foreign-language works, suggesting that William Bruce was a learned man. He studied horticulture extensively, and applied his knowledge of the subject in his own gardens at Kinross. He was a friend of James Sutherland of the Edinburgh Botanic Garden, and may have known John Evelyn and other English horticulturalists.
