English-born Australian author known for his novel His Natural Life (1874), an important literary work of colonial Australia.

At age 17 Clarke left England for Australia, where his uncle was a county court judge. After working briefly as a bank clerk, he turned to farming on a remote homestead. By 1867, however, he was writing stories for Australian Magazine and working as a theatre critic on the Melbourne Argus. Commissioned by the Australian Journal to write a serial about convict life, Clarke produced his masterwork, His Natural Life (also known as For the Term of His Natural Life, but the antecedent For the Term of was inserted without authority after his death), the story of Rufus Dawes, a man falsely convicted of a crime, who falls into the degradation of the convict world. It was written melodramatically in a style of almost garish realism. Clarke enjoyed good company and helped to found the Yorick Club, which numbered among its members many of the literary lights of his day.

His numerous novels and tales are collected in The Austral Edition of the Selected Works of Marcus Clarke (1890). A Colonial City: High and Low Life (1972), edited by L.T. Hergenhan, is a collection of his journalism.