He was the son of Francis Napier, 8th Lord Napier (1758–1823) and the father of Francis Napier, 10th Lord Napier and 1st Baron Ettrick (1819–1898). He served during the battle of Trafalgar (1805) as a midshipman. He later served as Lieutenant under Thomas Cochrane, 10th Earl of Dundonald.
A peer of Scotland, Lord Napier was an elected Scottish representative in the House of Lords from 1824 to 1832.
In December 1833, upon the ending of British East India Company’s monopoly on trade in the Far East, Lord Napier was appointed by Lord Palmerston, the foreign secretary and a family friend of Napier, the first Chief Superintendent of Trade at Canton (now Guangzhou), in China. He arrived at Macau on 15 July 1834, and Canton ten days later, with the mission of expanding British trade into inner China. Lacking the necessary diplomatic and commercial experience, he was not successful in achieving the objective.
Having failed to secure a meeting with the Viceroy of Canton, amid a litany of breaches of protocol, misunderstandings approaching complete communication breakdown and stubbornness on both sides, Napier’s frustration in failing to break an intractable trade deadlock led to his favoring a military solution. He sent the frigates Andromache and Imogene to Whampoa in plain breach of Imperial Viceroy Loo’s edict, with fatalities resulting on both sides in the skirmish of cannon fire as they breached the defences at the Bocca Tigris.
After a prolonged stalemate, Lord Napier was forced, sapped by typhus, to retire to Macau in September 1834, where he died of the fever on 11 October. He was buried in Macau, but later exhumed for reburial at his beloved Ettrick in Scotland. Napier was first to suggest establishment of a British presence on Hong Kong, then the site of a few small villages.
The Second and Third Superintendents were John Francis Davis and Sir George Best Robinson, respectively.
Lord Napier married Elizabeth Cochrane-Johnstone (c. 1795-1883), daughter of Scottish adventurer Andrew Cochrane-Johnstone, in 1816; they had two sons and five daughters. His eldest son, Francis Napier, also entered diplomatic service and was promoted by Palmerston for the rest of his life.
Following his death, the British Government placed a memorial to him before the Macao Customs Office. After being lost for a short time, it was moved to the Hong Kong Cemetery, and then to the Hong Kong Museum of History, where it now rests.