Adeyinka Adebayo was born in 1928, the son of a Public Works employee from Iyin Ekiti, near Ado Ekiti, (present day Ekiti State), Nigeria. He was educated at All Saints School, Iyin-Ekiti, and later attended Eko Boys High School and Christ's School Ado Ekiti. He joined the West African Frontier Force in 1948 as a regiment signaler and later completed the Officer Cadet Training Course in Teshie, Ghana from 1950 to 1952. After passing the War Office Examination for Commonwealth cadets in 1952 as well as the West African qualifying examination in 1953, he was commissioned as an officer in the Royal West African Frontier Force (RWAFF) as the 23rd West African military officer with number WA23 and 7th Nigerian military officer with number N7 after completing the War Office Cadet Training in Eaton Hall, England. He later attended the Staff College course in Camberley (Surrey) in 1960 and the prestigious Imperial Defence College, London in late 1965 where he was the only African officer.
Adeyinka Adebayo became an officer in 1953. His key career milestones are listed below:
Adebayo advised against the use of force in resolving the Biafran crisis. In one of the most prescient and articulate quotations of the war, he declared:
I need not tell you what horror, what devastation and what extreme human suffering will attend the use of force. When it is all over and the smoke and dust have lifted, and the dead are buried, we shall find, as other people have found, that it has all been futile, entirely futile, in solving the problems we set out to solve.