After the outbreak of World War II, he enlisted with the Australian Infantry Forces in 1940 and the following year was posted in Palestine but did not see active service.
[3] Fullbrook was to have a constant and wide ranging career as a painter, beginning in 1948 with his first joint exhibition at Tye’s Gallery with art school classmate Tim Nicholl.
He returned to Queensland where he befriended James Wieneke of Moreton Gallery and was employed by Richard Morley, founder of the Blake Prize.
That same year, he had a second solo show at the Moreton Gallery, Brisbane, and received honourable mention in the Archibald Prize for his portrait of his contemporary, potter Bernard Sahm.
[2] Leveson Street Gallery in a 1974 issue of The Bulletin, listed Fulbrook amongst the artists Dorothy Braund, Robert Dickerson, Nornie Gude, Hans Heysen, Louis Kahan, Mary Mac Queen, Helen Ogilvie, Lloyd Rees, Constance Stokes, and Roland Wakelin whom it represented.
[3] His oeuvre ranged over biblical themes, horse-racing, aboriginal Australians, Pilbara landscapes, Bondi, wildlife, floral works, and studio nudes.
[2] Fullbrook's light and airy works were soft figuration bordering on abstraction in high-tone coloured patches, but leaving the subject entirely recognisable.
Reviewing a 1995 National Gallery of Victoria exhibition, Racing Colors, art critic Robert Nelson described him as: "A colourist... Fullbrook's forte lies in the difficult balancing of patches of pinks and teal, or striations of lilac and dashes of cadmium green.
[3] Fullbrook married Janice Greenwood in 1966, but his wife suicided the following year, and is buried in the Walkerston Cemetery, Mackay, Queensland.