Robert Campbell, the son of Robert Campbell tertius of Buscot Park, Berkshire, England, and his wife, Anne Orr, was born probably in London on 8 January 1843. His father, grandfather and grandfather's uncle, all named Robert Campbell, had gained considerable wealth and influence in New South Wales importing and retailing, and wool and gold buying. He was educated at Eton College, and came to New Zealand, probably early in 1860, to buy or lease land on the family's behalf. By September 1860 Robert was in partnership with William Anderson Low in the Galloway run in Central Otago. In early 1863 he acquired Benmore station in North Otago, then Otekaieke in 1865, and the South Canterbury runs Rocky Point and Station Peak in 1869. In 1870 he leased the Burwood, Mararoa and Mavora runs in Southland. He began very active freeholding in the 1870s, reselling very profitably later in the decade. He also acquired property for development and resale in Manawatū.
Capable managers were largely responsible for developing the properties, but Campbell's brothers also managed various runs for brief periods. Campbell imported stud merino stock from Australia and won many prizes with them. He was active in both the Otago and North Otago Agricultural and Pastoral associations. His other business interests included coastal shipping, the Mosgiel Woollen Factory Company, the Oamaru Woollen Factory Company, and the Duntroon and Hakateramea [ sic ] Railway Company.
Campbell entered the House of Representatives as member for Oamaru in 1866. He resigned in 1869 to honeymoon in Britain with his wife, Emma Josephine Hawdon, whom he had married in Christchurch on 2 December 1868. He was appointed to the Legislative Council in 1870. His political career was not outstanding and he was frequently absent, returning to Britain in 1875 and 1881. He was more active in local affairs, as the first chairman of the Waitaki County Council (1877–81), a member of the Oamaru Harbour Board, the Waitaki High School Board, and the council (later senate) of the University of New Zealand (1871–79).
In 1881 Campbell's properties, many jointly owned with his father, were transferred to a newly formed London company, Robert Campbell and Sons, which in 1882 was the seventh-largest corporate landholder in New Zealand. Additional land leased in the names of various agents and managers eventually led to allegations of dummyism in 1885.
A stately mansion, designed in Scottish baronial style, was built at Otekaieke in 1876 as Campbell's home, and was the scene of many social gatherings. Drink increasingly diminished Campbell's efficiency in politics and business, and most local decisions in the company's affairs were made by the general manager, Alexander Campbell Begg, of Dunedin. After a long period of ill health Campbell died, childless, at Dunedin on 9 December 1889, aged 46. Emma Campbell died the following year.
Campbell, a young man of great promise, was a member of a powerful and wealthy family. With money generated by Australian business enterprises, he acquired vast areas of land in New Zealand and operated them on a scale seldom seen elsewhere in the country. Much of his land became plagued by rabbits, however, and its diminished capacity and falling wool prices caused the company to cease operations by 1920.