Keazor was born in Obosi, Eastern Nigeria (in what is now Anambra State) on 7 July 1907, to Justus Ikeazor Oboli I, a local chief and early convert to Christianity in Obosi.
The young Keazor gained admission into the newly founded Obosi Community School and then Dennis Memorial Grammar School in Onitsha in 1920 at the age of 13.