Spécialiste du portrait, il utilisait un appareil photo grand format. Commençant la photographie en 1949, il installe dans sa cour un studio. De 1962 à 1977, il est photographe à la Sûreté nationale.
Il a exposé grâce à Françoise Hughier aux Rencontres internationales de la photographie d’Arles en 1994, à la Fondation Cartier à Paris en 1994 et au musée Solomon R. Guggenheim à New York en 1996.
Un prix « Seydou Keïta » est attribué lors des Rencontres africaines de la photographie à Bamako.
Seydou Keïta was born in 1921 in Bamako, although the exact date is unknown. He was the oldest in a family of five children. His father Bâ Tièkòró and his uncle Tièmòkò were furniture makers. Keïta developed an interest in photography when his uncle gave him a Kodak Brownie with a film with eight shots in 1935, after returning from a trip to Senegal. In the beginning Keïta worked as both a carpenter and photographer, taking first portraits of his family and friends, later of people in the neighborhood. He learned photography and how to develop from Pierre Garnier, a French photographic supply store owner, and from Mountaga Traoré, his mentor. In 1948 he set up his first studio in the family house in Bamako-Koura behind the main prison.