Passing the Indian Civil Service examination in 1867, he went out to Bombay in November 1869, and served as an assistant collector.
Residing with his brother Robert at his father's old home, Achnashie, Rosneath, Dumbartonshire, he found recreation in gardening.
[2] A memorial tablet on the ruined wall of the old Rosneath church paid tribute to the example set by Campbell during the plague outbreak in Bombay, attributing to it his premature death.
Friends also founded a gold medal, conferred triennially by the Bombay branch of the Royal Asiatic Society, for work on Indian folklore, history, or ethnology.
William Wilson Hunter as editor of The Imperial Gazetteer of India largely based the Bombay portions on Campbell's work.
Campbell completed his Bombay Gazetteer at the end of 1901, in 34 volumes, and 26 sections; he himself wrote in those dealing with ethnology.
He published a history of Mandogarh in the Journal of the Bombay Branch, Royal Asiatic Society (vol.
1895–7); papers in the proceedings of the Bombay Anthropological Society; and studies of demonology, under the title of Notes on the Spirit Basis of Belief and Custom, in the Indian Antiquary from 1894.