From 1861 to 1867 Besant taught at the Royal College, Mauritius, and in 1868 he became secretary to the Palestine Exploration Fund. In 1871 he began a literary collaboration with James Rice, editor of Once a Week, which lasted until Rice's death (1882). During that time they produced 14 romantic, improbable, and verbose novels.

In 1882 Besant published his first independent novel, entitled All Sorts and Conditions of Men and based on his impressions of the East London slums, which he saw as joyless rather than vicious places. The “Palace of Delights” that he projected in his book became a reality when the People's Palace was founded (1887) in Mile End Road, London, in an attempt to provide education and recreation to the slum dwellers of the area; Besant cooperated in its establishment. His book Children of Gibeon (1886) also described slum life.

Besant wrote 32 novels in the 19 years after Rice's death, including Dorothy Forster (1884) and Armorel of Lyonesse (1890). His biographies include Rabelais (1879), and he also wrote a long series of historical and topographical studies (1902–12) of London. He helped to found the Society of Authors in 1884 and edited its journal until his death. Besant was knighted in 1895.