Mary Henrietta Kingsley was born in Islington, London on the 13 October 1862. A niece of the clergyman and author Charles Kingsley, she led a secluded life until age 30, when she set out alone to visit West Africa and to study African religion and law. She hoped this research would help her complete a book left unfinished by her deceased father, George Henry Kingsley.

During 1893 and 1894 Mary Kingsley visited Cabinda, a coastal district of Angola; Old Calabar in southeast Nigeria; and the island of Fernando Po (now Bioko), part of Equatorial Guinea, near the Cameroon coast. Around the lower Congo River she collected specimens of beetles and freshwater fish for the British Museum.

Returning to Africa in December 1894, Kingsley visited the French Congo and then journeyed to Gabon. In this area, parts of which had never before been visited by a European, she had many adventures and narrow escapes travelling up the Ogooué River through the country of the Fang, a tribe known for cannibalism. She then visited Corisco Island, off Gabon, and also climbed Mount Cameroon. Kingsley returned to England in November 1895 with a collection of valuable zoological specimens, three of which were entirely new and were named after her. Between 1896 and 1899 she lectured widely throughout her homeland.

Kingsley died on the 3 June 1900 in Simonstown, near Cape Town, Cape Colony (now in South Africa) while nursing sick prisoners during the Boer War.