Osborne’s grandfather, Sir Edward Osborne†, came from a minor gentry family from Kent but was apprenticed to a leading London merchant. Having married his master’s daughter, he accumulated a substantial mercantile fortune and was elected to Parliament for the City in 1586. His wife brought him substantial properties, principally in London, Essex and Yorkshire, but they also included the manor of Bilby in Nottinghamshire, four-and-half miles north-west of East Retford. His son, Sir Hewett Osborne, retained at least some of his business interests in London, investing in trade with the Ottoman Empire. He served with distinction as a soldier under Peregrine Bertie, 13th Lord Willoughby of Willoughby, Beck and Eresby, in France and Robert Devereux, 2nd earl of Essex, in Ireland, where he died on active service.
As his father died when he was still a minor, Osborne became a ward of the Crown. His mother and her brother, (Sir) George Fleetwood, purchased his wardship in June 1600 for £420.
Osborne was probably nominated for East Retford in 1628 by Sir Gervase Clifton*, the high steward of the borough, to whom Osborne sold his property at Bilby at some unspecified date. Osborne was connected with Clifton via his stepfather, Sir Peter Frescheville, whose father’s first wife had been Clifton’s aunt. Frescheville appointed Osborne and Clifton supervisors of his will in 1633, describing the latter as his ‘kind friend and ally’.
Osborne was one of Wentworth’s closest supporters, deputizing for him in the Council in the North when Wentworth was appointed Ireland’s lord deputy, in which capacity (Sir) John Coke* found Osborne ‘a young man of good understanding, and counsellable, and very forward to promote His Majesty’s service’.
