Master was the eldest son of Sir Streynsham Master, governor of Madras from 1677 to 1681, and director of the East India Company, of Codnor Castle, Derbyshire and his second wife Elizabeth Legh, daughter of Richard Legh, M.P., of Lyme, Cheshire.
He was educated at Isleworth school Middlesex, and was admitted at St John's College, Cambridge 23 June 1711.
At the 1727 British general election he was returned as Tory Member of Parliament for Newton by his uncle, Peter Legh of Lyme, the proprietor of the borough.
He was returned again for Newton at the 1741 British general election, but on 16 December 1741, he was again absent from a division on the chairman of committees.
[2] He and his first wife Margaret had eight children:[3] His son Legh went to Maryland in America, where his life and death gave rise to folklore and legend.