William Clarke, the son of the son of John Scott Clarke, a prosperous businessman, was born in Norwich on 22nd November 1852. He worked for his father after leaving school but in 1872 he entered Cambridge University. Clarke became a Unitarian and after graduating became a journalist for the Nonconformist press.
Clarke was greatly influenced by the writings of Thomas Carlyle and John Ruskin and rejected bourgeois individualism as "the evil of the nineteenth century". After reading Henry George he became a supporter of land nationalization.
In 1883 he joined the Fellowship of the New Life, an organisation founded by Thomas Davidson. Other members included Edward Carpenter, Edith Lees, Edith Nesbit, Isabella Ford, Henry Hyde Champion, Havelock Ellis, Frank Podmore, Hubert Bland, Edward Pease and Henry Stephens Salt. According to another member, Ramsay MacDonald, the group were influenced by the ideas of Henry David Thoreau and Ralph Waldo Emerson.
In January 1884 some of the members of the group, including Clarke, decided to form a socialist debating group. Frank Podmore suggested that the group should be named after the Roman General, Quintus Fabius Maximus, who advocated the weakening the opposition by harassing operations rather than becoming involved in pitched battles. They therefore decided to call themselves the Fabian Society. Clarke was not very active at first but in 1888 he joined the Fabian's executive committee and contributed the article, the Industrial Basis of Socialism, to the book Essays in Fabian Socialism, that was edited by George Bernard Shaw in 1889.
William Clarke fell in love with Edith Lees, a woman he had met at a meeting of the Fellowship of the New Life. According to her friend, Havelock Ellis: "Their social ideals and aspirations were singularly alike, and held with a like fervour and sincerity. But her temperament was much more buoyant, inspiring, and genial in personal intercourse. It was therefore natural that he should often come and spend hours in her rooms, frequently arriving in the deepest dejection and going away a totally different man.... There was no suggestion of love; into her mind at all events the idea had never entered. But when one day she met him in Gray's Inn and gaily announced her approaching marriage he suddenly changed countenance, she told me, and seemed to have been struck a great blow. From that moment he ceased to seek to meet her, and he avoided me; I believe I never saw and scarcely heard from him again, and he no longer took any friendly interest in my books, though it is not likely that my later books would in any case have appealed to him."
Clarke had originally supported the Liberal Party but in 1895 he helped establish The Progressive Review. Clarke became editor and the main objective was the creation of a new progressive political party. The journal ceased publication in 1896.
Clarke disagreed with the decision by the Fabian Society to support the Boer War and as a result left the organisation. He also left his position as staff reporter on The Daily Chronicle over this issue. According to his biographer, Peter Weiler: "Clarke became increasingly bitter and disillusioned. He had already drifted away from the Fabian Society because it failed to fulfil his fundamental spiritual and ethical goals. Now the collapse of his own political project and the growth of imperialist sentiment, which he abhorred, filled him with such despair that he withdrew from active involvement in political causes to concern himself with philosophy and art."
Havelock Ellis has argued that Clarke suffered from depression after Edith Lees got married. He (Clarke) was... a man of neurotic temperament... a creature of moods, of profound depressions, of frequent illnesses, with an organism full of toxins." His biographer agrees with this analysis: "Prone to self-pity, he complained frequently about his own lack of success and need to work so hard. In his last years, he suffered as well from serious depression, made worse by loneliness, the death of his mother, and financial setbacks."
William Clarke, who suffered from diabetes, continued to work as a journalist and contributed articles to The Spectator and The Economist. Clarke died, unmarried, on 8th May 1901 in Mostar, Herzegovina, while on holiday in south-east Europe.