The increasing strength of the French in southern Italy made his duties arduous, and Bunbury says that few officers could have discharged them with better judgment and with more unwearied activity and zeal, and that none of the British commanders baffled so completely the intrigues of the court of Palermo. He describes Sherbrooke as ‘a short, square, hardy little man, with a countenance that told at once the determined fortitude of his nature’ (Narrative of some Passages in the Great War).
His temporary command having come to an end by the arrival of Sir J. Stuart, he went home in June. He had been made colonel of the Sicilian regiment on 5 Feb. 1807, and was transferred to the 68th foot in May 1809. In January 1809 he was sent out with four thousand men to garrison Cadiz, but on arrival there he received orders to go to Lisbon, where he landed with his troops on 12 March. Finding that Beresford, who was three years his junior, had been appointed to command the Portuguese army with the local rank of lieutenant-general, he asked for and obtained the same local rank.
He was second in command to Wellesley in the campaign of 1809. At the passage of the Douro his division (the 1st) crossed the river opposite Oporto, and helped to drive the French out of the town. At Talavera it was in the centre of the British line, and brilliantly repulsed the attack made upon it by Lapisse's division of Victor's corps. But one brigade, the guards, following the enemy too far, and taken in flank as well as in front by the French artillery, suffered heavily. The division fell back in some confusion, and the British centre might have been pierced if it had not been for the timely advance and steady bearing of the 48th. In Wellesley's despatch, as well as in his general orders, the manner in which Sherbrooke led his division to the bayonet charge was particularly mentioned; and it was notified by the commander-in-chief (in general orders of 18 Aug.) that his conduct had entitled him to the king's marked approbation. He was made K.B. on 16 Sept., and received the Talavera medal. Wellington long afterwards told Lord Stanhope, ‘Sherbrooke was a very good officer, but the most passionate man, I think, I ever knew;’ and he mentioned as an instance, that in his own presence at Oporto his interpreter so irritated Sherbrooke that he could hardly keep his hands off him. A fortnight before Talavera Wellesley wrote to Sherbrooke to impress upon him that he must not abuse commissariat officers, however much he might think they deserved it (cf. Stanhope, Conversations, p. 256).
Sherbrooke's health, never strong, now broke down, and he returned to England in May 1810. He became lieutenant-general on 4 June 1811, and on 19 Aug. he was appointed lieutenant-governor of Nova Scotia. The declaration of war by the United States on 18 June 1812 made it necessary for him to take measures for the defence of the colony, and he did this with so much vigour and judgment that, when peace had been concluded, 1,000l. was voted to him for the purchase of plate. In September 1814 he commanded the military portion of an expedition up the Penobscot, which was carried out most successfully in ten days, and did something to counterbalance the British failure at Plattsburg. An American brigade capitulated, and the port of Maine, which lies between the Penobscot and New Brunswick, was for the time being made a British possession. A portrait of Sherbrooke was placed in the province building at Halifax at the end of his term of office, and a township still bears his name.
On 29 Jan. 1816 he was appointed captain-general and governor-in-chief of Canada, but he was not sworn in at Quebec till 12 July. The struggle then going on between the dominant minority and the French catholic majority made the post far from enviable; but he succeeded in winning the personal esteem of the colonists. The strain of the situation, however, told on his highly strung temperament; on 6 Feb. 1818 he had a paralytic stroke, which caused him to send home his resignation, and he left Quebec on 12 Aug. He spent the rest of his life in retirement at Calverton, Nottinghamshire and died there on 14 Feb. 1830. He was buried at Oxton. He had been transferred from the colonelcy of the 68th to that of the 33rd regiment on 1 Jan. 1813, received the G.C.B. on 2 Jan. 1815, and was promoted general on 27 May 1825. On 24 Aug. 1811 he married Katherine, daughter of the Rev. Reginald Pyndar, rector of Madresfield, Worcestershire. She died without issue on 15 May 1856. Her sister and coheiress was the mother of Robert Lowe, afterwards Viscount Sherbrooke [q. v.], whose great-grandmother, on the father's side, was sister of Sir J. C. Sherbrooke's mother.
There is a portrait of Sherbrooke at Oxton Hall, and a miniature, taken in 1796, reproduced as frontispiece to Martin's ‘Memoir.’
[Martin's Memoir, appended to Life and Letters of Viscount Sherbrooke; Gent. Mag. 1830, i. 558; Hook's Life of Sir D. Baird, i. 211; U.S. Magazine, 1830, i. 519; Wellington Despatches, Supplementary, vi. 261, 321; Murdoch's Hist. of Nova Scotia.]