John Campbell was born in Edinburgh in March 1766. He lost his father at age two and his mother at age six, and was raised by an uncle. He studied at the Royal High School alongside the future writer Walter Scott, and worked as an apprentice goldsmith before entering the Christian ministry.
In Edinburgh, he founded the Religious Tract Society of Scotland in 1793. In the following years, alongside the itinerant preacher James Haldane, he also helped rapidly multiply Sunday schools across the region. He became pastor of the Kingsland Congregational Chapel in London in 1802, and used the pulpit to stir interest in missions to Africa, then largely unknown to the English.
In 1812, already a director of the London Missionary Society, he was sent to the Cape of Good Hope to inspect the mission stations of southern Africa. He set out from Cape Town in 1813 and traveled thousands of miles through Bethelsdorp, Graaff-Reinet, Griquatown, and the territory of the Batlhaping, led by chief Mothibi.
Back in London, he published Travels in South Africa (1815), one of the first detailed accounts of the peoples of the interior of what is now Botswana and South Africa. The book stirred great interest among the British public in African missions.
Between 1819 and 1821, he made a second journey, this time accompanied by the missionary John Philip. On this visit, he guided the young Robert Moffat to begin a work among the Batswana people. Moffat first settled in Dithakong (also called Lattakoo) and only years later, in 1825, moved the station to Kuruman, which would become one of the most influential mission posts of southern Africa in the 19th century.
Like many missionaries of his generation, Campbell mixed the proclamation of the gospel with an almost uncritical confidence in European civilization, treating African customs as backwardness to be corrected. Nineteenth century historians such as George McCall Theal also pointed to another limitation of Campbell as a writer: the simplicity and credulity of his accounts, which made much of what he described about episodes he had not witnessed firsthand unreliable. Both points are recognized today as historical limits of his work.
Back in England, he became one of the first writers to produce missionary literature for children, and for years edited The Youth’s Magazine. His travel accounts helped awaken in an entire generation an interest in the evangelization of the African continent.
Campbell died in London on April 4, 1840, at the age of 74, after decades devoted to the cause of missions.