Hamblin was born in Pentonville, England. He apprenticed in a London business but changed course after a successful performance as Hamlet in a school production. By 1815, he had made his professional debut as a ballet dancer at London's Adelphi Theatre. He toured the British Isles over the next eight years, performing at venues such as the Drury Lane Theatre (for manager Stephen Kemble) and Sadler's Wells Theatre. He married Elizabeth Blanchard, a popular actress and daughter of actor William Blanchard and half-sister of actor/playwright E. L. Blanchard. Hamblin had two children by his first wife: William Henry Hamblin Jr. (stage name "Thomas Hamblin Jr") and Elizabeth "Betsey" Hamblin.