Grant Allen was born Charles Grant Blairfindie Allen on February 24, 1848, in Kingston, Canada. He was the second and only surviving son of Joseph Antisell Allen, a minister of the Irish church, and Charlotte Ann Grant, daughter of the fifth baron de Longuiel, a French title recognized in Canada. He was first educated by his father, then by a Yale tutor when the family moved to Connecticut. Later, he was sent to private school in Dieppe, France, at the Collège Impériale. From there, he went on to the King Edwards School, Birmingham, and then to Oxford University, where he received a first-class degree in classical moderations in 1871. While at Oxford, Allen married, but his wife became ill soon after their marriage and died within two years.
In 1873, Allen was appointed professor of mental and moral philosophy at the first university for blacks established in Jamaica. Just before leaving for this post, he married Ellen Jerrad, who accompanied him there. As a teaching position, this appointment was a failure. Most of the students were not literate; they were hardly prepared for a study of “mental and moral philosophy.” Allen used his extra time there, however, to formulate his evolutionary system of philosophy.
In 1876, the school collapsed, following the death of its founder, and Allen returned to England. On his return, he supported himself and his family by writing. At first he wrote only scientific essays, but later he began adapting his scientific ideas to a fiction format. His first novel, Philistia, was published in 1884. He would go on to write more than thirty works of fiction, including detective novels: An African Millionaire, published in 1897; Miss Cayley’s Adventures, published in 1899; and Hilda Wade, published in 1900.
In 1892, Allen had acquired a famous neighbor, Arthur Conan Doyle. Although he and Doyle held diametrically opposed political, social, and religious views, they became good friends. In 1899, Allen, realizing that he was dying, asked Doyle to complete the last two chapters of Hilda Wade. Doyle followed through on his promise to do so, though he admitted that he was never happy with the result. Allen died on October 28, 1899, of liver disease. He was survived by his wife and a son.