The Supreme Military Council in Nigeria was established by:

The Supreme Military Council (SMC) was the highest decision-making body during periods of military rule in Nigeria. It was established by General Aguiyi Ironsi following the first military coup of 15 January 1966.

After the coup, which overthrew the civilian government of Prime Minister Tafawa Balewa, Major General Johnson Aguiyi Ironsi (then the most senior military officer) assumed power as Head of State. He created the Supreme Military Council as the apex governing body to replace the civilian legislative and executive institutions. The SMC comprised the most senior military and police officers and served as the final authority on policy, governance, and legislation.

Ironsi's SMC issued Decree No. 1 of 1966, which suspended parts of the constitution, dissolved parliament, and vested executive and legislative authority in the Federal Military Government headed by the SMC.

While Yakubu Gowon, Murtala Mohammed, and Muhammadu Buhari all served as military heads of state who governed through the SMC at different times, none of them created the institution. Gowon succeeded Ironsi after the July 1966 counter-coup, Murtala Mohammed took over in 1975, and Buhari came to power in 1983.

Exam tip: Aguiyi Ironsi is associated with two key firsts in Nigerian military governance: he was the first military Head of State, and he established the Supreme Military Council.