William Forster was the grandson of the explorer, Gregory Blaxland. He was educated at the W. T. Capes School in Sydney before finishing his education at The Kings School, where he won a poetry prize. After completing his education Forster used his family resources to become a prosperous pastoralist, owning land in both New South Wales and Queensland. In 1856 his keen interest in politics saw him elected to the New South Wales Legislative Assembly and he was still a member of the New South Wales Parliament at the time of his death. During his political career Forster held various positions, including Premier in 1859-1860 and Agent General in London in 1876.
As an author, Forster was known for his drama and verse, particulary the satire The Devil andthe Governor. He was also the author of a number of political pamphlets and a handbook on emigration.