Slessor made his living as a newspaper journalist, mostly for the
Sydney Sun, and was a war correspondent during World War II (1939 – 1945). Slessor counted Norman Lindsay, Hugh McCrae and Jack Lindsay among his friends.
The bulk of Slessor's poetic work was produced before the end of the Second World War. His "Five Bells", relating to Sydney Harbour, remains probably his best known poem, followed by "Beach Burial", a tribute to Australian troops who fought in World War II.
In the New Year's Honours of 1959, Slessor was appointed an Officer of the Order of the British Empire for services to literature.
In 1965, Australian writer Hal Porter wrote of having met and stayed with Slessor in the 1930s. He described Slessor as:
"...a city lover, fastidious and excessively courteous, in those qualities resembles Baudelaire, as he does in being incapable of sentimentalizing over vegetation, in finding in nature something cruel, something bordering on effrontery. He prefers chiselled stone to the disorganization of grass".
Slessor also wrote on rugby league football for the popular publication
Smith's Weekly.