He then became an assistant to photographers Olga Sharpe and Max Dupain, studied cooking and in 1956 he opened an espresso bar and art gallery in Rowe Street, Sydney.
[5] Horton served as secretary of the Society of Artists, an executive member of the Arts Council of Australia (NSW Division), a board member of the National Trust of Australia (NSW), a trustee of the Art Gallery of New South Wales and an Australian commissioner for the XIIIth Bienal Internacional de São Paulo.
He met Lenwood Morris, a dancer with the Katherine Dunham black American company, and he was his first regular male lover.
A generous host, Horton gave lavish parties at his Palm Beach weekender and his home at Potts Point.
[8] On his death one-fifth of the residue of the estate went to two daughters of Christopher Davis, another fifth to two cousins, and the remaining three-fifths to the National Trust and the Art Gallery of New South Wales.
[9] It was a condition of Horton's bequest to the Art Gallery of New South Wales that it display annually a painting of himself by Australian artist, Bryan Westwood.