Olusegun Obasanjo and Muhammadu Buhari both served two non-consecutive periods as head of state, first as military officers and then later as civilians.
[4] Olusegun Obasanjo served the longest period for eleven years, two hundred and thirty days combined.
[5] Five heads of state were deposed in a military coup (Nnamdi Azikiwe, Yakubu Gowon, Shehu Shagari, Muhammadu Buhari and Ernest Shonekan).
[9] Olusegun Obasanjo was the first vice president (as Chief of Staff, Supreme Headquarters) to become head of state when Murtala Muhammed was killed during the 1976 coup attempt,[10] while Goodluck Jonathan was the first democratic vice president to become head of state when Umaru Musa Yar'Adua died of Illness on 5 May 2010.
Major Chukwuma Kaduna Nzeogwu orchestrated the bloody military coup d'état of 1966 which overthrew the First Republic.
Major General Muhammadu Buhari was made military head of state following the coup d'ètat of 1983, which overthrew the Second Republic.
General Sani Abacha led the palace coup d'ètat of 1993 which overthrew the Interim National Government.
Of the 14 post monarchy heads of state, only two, Olusegun Obasanjo and Muhammadu Buhari, served in two non consecutive periods.