Major General Sir John Campbell, 2nd Baronet, of New Brunswick, Canada, (14 April 1807 – 18 June 1855), was a British army officer and the son of General Sir Archibald Campbell, 1st Baronet of New Brunswick, Canada. He died in the Battle of the Great Redan.
John Campbell was born on 14 April 1807, the second son of General Sir Archibald Campbell, 1st Baronet,(1769-1843) and Helen, daughter of Capt. John McDonald or MacDonald, of Garth, Perthshire, Scotland. The Campbells were members of the Smalls of Dirnanean in Perthshire. The Rev. Archibald Campbell, the elder son and heir to the baronetcy, died unmarried in 1831 serving as a chaplain in India. After his brother's death, John Campbell became his father's heir.
Campbell showed early skills as an artist, painting or sketching early gatherings and events in New Brunswick while his father served as Lieutenant-Governor of New Brunswick. Today a number of those portraits are in the possession of the Provincial Archives of New Brunswick.
Campbell entered the army as an Ensign in the 38th regiment, which his father then commanded, in 1821, joining the regiment in India. He served as aide-de-camp to his father throughout the first Burmese War, and on 1 July 1824 he was promoted a Lieutenant, without purchase, and in 1826 thanked by the governor-general in council for his services. On 11 July 1826 he was promoted to a company and remained in Burmah in a civil capacity until 1829, when he returned to England and joined the depôt of his regiment.
From 1831 to 1887 Campbell acted as aide-de-camp to his father when serving as Lieutenant-Governor of New Brunswick, and in the latter year he purchased the majority of his regiment. In 1840 he purchased the lieutenant-colonelcy of the 38th, and commanded it continuously in the Mediterranean, the West Indies, and Nova Scotia, until he was selected for the command of a brigade in the expeditionary force intended for the East in 1854.