Morrison was born in the East End of London, on November 1, 1863. Little is known about his childhood and education, though he was probably educated in the East End. By 1886 he was working as a clerk at the People's Palace, in Mile End. In 1890 he left this job and joined the editorial staff of the Evening Globe newspaper. The following year he published a story entitled A Street which was subsequently published in book form in Tales of Mean Streets. The volume was a critical success, but a number of reviewers objected to the violence portrayed in one story, Lizerunt.
Around this time Morrison was also producing detective short stories which emulated those of Conan Doyle about Sherlock Holmes. Morrison's Martin Hewitt was an imitation of Sherlock Holmes, but inverted: he was ordinary, short, good tempered and gladly cooperated with the police. He was not particularly original but some of these stories hold up today. Three volumes of Hewitt stories were published before the publication of the novel for which Morrison is most famous: A Child of the Jago (1896). The novel described in graphic detail living conditions in the East End including the permeation of violence into everyday life (it was a barely fictionalised account of life in the Old Nichol Street Rookery). Other less well-received novels and stories followed, until Morrison effectively retired from writing fiction around 1913. Between then and his death, he seems to have concentrated on building his collection of Japanese prints and paintings.