He is the elder son of Sir George Osborne, 16th Baronet, who as an officer in the Royal Sussex Regiment, was decorated during the First World War, and Mary Horn.

Osborne was educated at Wellington College, Berkshire, and received an MA from Christ Church, Oxford.

He succeeded to the baronetcy, becoming the 17th Osborne baronet of Ballentaylor and Ballylemon, on 21 July 1960, upon the death of his father.

[citation needed] Osborne's personal wealth, amassed through inheritance and his business career, has been the subject of controversy during his son's political career, especially after an interview with the Financial Times in which he discussed his "expensive tastes", such as the purchase of a £19,000 Italian desk.

[2][3][4] On 16 October 1968 Osborne married Felicity Alexandra Loxton-Peacock of Belgravia, London (who subsequently married, in 1979, Sir Anthony Grover, chairman of Lloyd's Register of Shipping, who died in 1981, and thirdly, in 1983, Sir James Dunnett[5]).