He had an elementary education in County Tyrone and inherited his father's property.

In 1829, on the advice of two brothers who had already emigrated to New South Wales, he liquidated his assets for £3000 and invested in a consignment of Irish linen which he exported to Sydney.

From the proceeds of the linen he acquired a land grant of 2,560 acres and established a dairy farm at Marshall Mount near Dapto.

By 1850, Osborne had acquired further substantial property in the Illawarra and Murrumbidgee districts and had also developed coal mines at Mount Keira and Maitland.

[1] In 1851, prior to the establishment of responsible government, Osborne was elected to the semi-elected Legislative Council.