Owner of Wilton House, Wilts., he studied at Christ Church College, Oxford, in the time of Aldrich, and was active in promoting the Palladianism that Inigo Jones had introduced, and which was being revived in Herbert's lifetime under the aegis of Burlington. He became an important amateur, probably more faithful to Palladian principles than either Burlington or Kent. He and Roger Morris appear to have designed the elegant bridge at Wilton (1736–7), Marble Hill, Twickenham (1724–9), White Lodge, Richmond New Park (1727–8), and other works. Campbell also worked for or with Herbert, notably in connection with the latter's house in Whitehall, London (1724), and, it seems, Marble Hill. It is probable that Herbert, lacking practical architectural skills, worked with Morris as his amanuensis.
Colvin (1995);Oxford Dictionary of National Biography (2004)