Kosoko was a member of the Ologun Kutere Lagos Royal Family who reigned as Oba of Lagos from 1845 to 1851. His father was Oba Osinlokun and his siblings were Idewu Ojulari, Olufunmi, Odunsi, Ladega, Ogunbambi, Akinsanya, Ogunjobi, Akimosa, Ibiyemi, Adebajo, Matimoju, Adeniyi, Isiyemi, Igbalu, Oresanya, and Idewu-Ojulari.

The Oba of Lagos, also known as the Eleko of Eko, is the traditional ruler (Oba) of Lagos.