[1] Though born in Rode, Somerset, Gilman spent his early years at Snargate Rectory, in the Romney Marshes in Kent, where his father was the Rector.

Although he developed an interest in art during a childhood convalescence period, Gilman did not begin his artistic training until after his non-collegiate year at Oxford University (cut short by ill health) and after working in Ukraine as a tutor to a British family in Odessa (1895).

At this time he met the American painter Grace Cornelia Canedy; they had both been copying Velázquez in the Museo del Prado in Madrid.

Harold Gilman was married, for the second time, to (Dorothy) Sylvia Hardy (formerly Meyer),[3][4] an artist he had met at Westminster and who had studied with him since 1914.

In the meantime he joined the Allied Artists' Association, moved to Letchworth, and began to show influence from work of Vuillard as well as Sickert.

He soon outpaced Sickert's understanding of post-Impressionism and moved out from under his shadow, using ever stronger colour, under the influence of Van Gogh, Gauguin and Signac.

He taught at the Westminster School of Art where he influenced students who included Mary Godwin,[6] Ruth Doggett, and Marjorie Sherlock.