 He entered Balliol College, Oxford, aged 16 on 28 February 1724.In 1728, he inherited the substantial estates of his uncle Sir William Blackett, 2nd Baronet, at Cambo and Allendale, Northumberland, on condition that he married Elizabeth Orde (his uncle's natural daughter) within twelve months and adopted the name and coat of arms of Blackett.The marriage took place on 29 September 1729 at Newcastle.