Horne was born in Chiswick, Middlesex and educated at Westminster School and Christ Church, Oxford.

[2] Horne travelled to Van Diemen's Land with his wife and two daughters, arriving in Hobart Town on 31 January 1830.

He was soon engaged in local politics, opposing the governor, Sir George Arthur and editing the Colonist newspaper.

[2] This appointment attracted criticism from the press due to Horne's financial history, and was unsuccessfully challenged in the Supreme Court.

[2] Horne was elected to the Legislative Council as member for Hobart, along with William Carter and James Milne Wilson.