Forbes MacBean was born at Warkleigh, Devon on 12 October 1825, third of the seven children of Forbes MacBean (31 January 1789-19 June 1853) and his wife Eliza Wohrmann (1788-18 March 1866), who was born at St Petersburg, Russian and a stepdaughter of George Scougall of London, who married at Edinburgh on 12 October 1819. Forbes, jun. married at St Cuthbert's Church in Ormesby, Yorkshire on 17 July 1855, Francis Maria Pennyman (1833-21 September 1912), daughter of James Stovin Pennyman of Ornesby Hall, and Mary Mackenzie of Naburn Hall, York, and they had three sons and a daughter. Forbes was an army officer, serving in the 92nd Highland Brigade and the 6th Battalion West Yorkshire Militia 1855-1876.

A committee member of the Rugby Art & Industry exhibition which was held in Rugby Town Hall in 1873 and as Col. MacBean, in 1880 he exhibited some of his paintings at the Bury St Edmund's Fine Art Society including 'Study of an Old Woman's Face' (109) when living at Heath House, Livermere, Suffolk. He then returned to London and took a position in the Lord Chamberlain's Department and in 1891 was a 65 year old retired Lieutenant Sergeant At Arms to the Queen, and Justice of the Peace, living at Victoria Park, St James, Eastry, Kent with his 58-year-old wife Frances and two of their children, 34 year old Forbes, born at Gibraltar with a wife 29 year old Mary, born Dedham, Essex, and 17-year-old Marion, born at Rugby, Warwickshire. Forbes MacBean died at 18 Victoria Park, Dover, Kent on 23 October 1900 and buried in St Mary's Cemetery 3 days later.