Robert Campbell was born on June 21, 1835, in Drummond, Lanark County, Ontario.

He was a Presbyterian minister, botanist, educator, and author. He graduated from Queen’s College, Kingston (B.A., 1856; M.A., 1858) and became headmaster of Queen’s College School in 1856. In 1862, he was ordained and inducted into St. Andrew’s Church in Galt, Cambridge, Ontario. In 1866, he accepted a call from the famous Scottish Presbyterian Church of St. Gabriel Street Church in Montreal where he would serve until his retirement in 1909. He held the title of minister emeritus from 1909 until his death. Proud of his Scottish heritage, Campbell was a founding member of the Celtic Society of Montreal, established in 1883. He was a member of the board of managers of the Presbyterian College of Montreal (1875-1883) and he also taught church history there (1904-1905, 1916). An amateur naturalist, he collected avidly wherever he went in North America and Europe. He donated an extensive collection of 2765 sheets to the McGill University Herbarium. He was the author of several papers and articles dealing with the flora of the island of Montreal, the Rocky Mountains, and North American goldenrods, published in the Canadian Record of Science. He also wrote the book "A History of the Scotch Presbyterian Church, St. Gabriel Street, Montreal" (1887).

In 1863, he married Margaret Macdonnell (1841–1912). He died on March 13, 1921, in Outremont, Montreal, Quebec.