He was born in Bailieboro, County Cavan, Ireland in 1850, the son of merchant Richard Clarke, and came to Toronto in 1864 after the death of his father. He apprenticed as a printer with the Toronto Globe, later working with The Toronto Mail. In 1872, he was one of the leaders of a printers' strike in the city. In 1884, he married Charlotte Elizabeth Scott. Clarke was printer and publisher of the Sentinel, a newspaper associated with the Orange Order, and also served as mayor of Toronto. He was also manager of the Excelsior Life Insurance Company of Toronto. He died at home in Toronto in 1905.