Clarke is the younger son and third child of Joshua Clarke and Brigid Clarke (née MacGonigal). Church decorator Joshua Clarke moves to Dublin from Leeds in 1877 and starts a decorating business, Joshua Clarke & Sons, which later incorporates a stained glass division. Through his work with his father, Clarke is exposed to many schools of art but Art Nouveau in particular.
Clarke is educated at the Model School in Marlborough Street, Dublin and Belvedere College, which he leaves in 1905. After his mother’s death in 1903, he is apprenticed into his father’s studio and attends evening classes in the Metropolitan College of Art and Design. His The Consecration of St. Mel, Bishop of Longford, by St. Patrick wins the gold medal for stained glass work in the 1910 Board of Education National Competition. At the art school in Dublin, he meets fellow artist and teacher Margaret Crilley. They marry on October 31, 1914.
Clarke moves to London to seek work as a book illustrator. Picked up by London publisher George G. Harrap and Co., he starts with two commissions which are never completed. Difficulties with these projects makes Fairy Tales by Hans Christian Andersen his first printed work, in 1916. It includes 16 colour plates and more than 24 halftone illustrations. This is followed by an illustrations for an edition of Edgar Allan Poe‘s Tales of Mystery and Imagination, the second version of which, published in 1923, makes his reputation as a book illustrator. His work can be compared to that of Aubrey Beardsley, Kay Nielsen, and Edmund Dulac. His final book, Selected Poems of Algernon Charles Swinburne, is published in 1928.
Clarke also continues to work in stained glass, producing more than 130 windows. His glass is distinguished by the finesse of its drawing and his use of rich colours. He is especially fond of deep blues. His use of heavy lines in his black-and-white book illustrations echoes his glass techniques.
Clarke’s stained glass work includes many religious windows, including the windows of the Honan Chapel in University College Cork. He also produces much secular stained glass such as a window illustrating John Keats‘ The Eve of St. Agnes (now in the Hugh Lane Gallery in Dublin) and the Geneva Window, (now in the Wolfsonian Museum, Miami Beach, Florida). Perhaps his most seen works are the windows he creates for Bewley’s on Dublin’s Grafton Street.
Clarke is plagued with ill health, in particular respiratory problems. He is diagnosed with tuberculosis in 1929 and goes to a sanatorium in Davos, Switzerland. Fearing that he will die abroad, he begins his journey back to Dublin in 1931, but dies on this journey on January 6, 1931 in Chur where he is buried. A headstone is erected but local law requires that the family pledge to maintain the grave 15 years after the death. This is not explained to the Clarke family and Harry Clarke’s remains are disinterred in 1946 and reburied in a communal grave.