Stephensen was an Australian nationalist writer and activist. He became active in several communist groups in his youth and was later recruited by the British intelligence service MI6 to infiltrate their intellectual groups and inner circles, feeding them information. He developed far right political leanings as a writer, wishing to cultivate a nationalist culture within Australian literacy that would clearly identify Australian literature as unique and exempt from foreign influence, resulting in the founding of the Jindyworobak Movement.
Stephensen’s writing reflected strong tones of racism, anti Semitism and xenophobia that openly opposed multiculturalism and immigration. He became a leading figure in the Australian anti communist pro fascist organisation the Australia First Movement. Stephensen became an advocate of Australian collaboration with the Imperial Japanese forces against the Allies. He was imprisoned for three years as a result of his wilful advocating of treason.
He died of natural causes in 1965.