An ethnic Tutsi, Buyoya joined the sole legal party, UPRONA and quickly rose through the ranks of the Burundian military.

In 1987, he led a military coup d'état that overthrew his predecessor Jean-Baptiste Bagaza and enabled him to seize power.

Buyoya then established a National Reconciliation Commission that created a new constitution in 1992 which allowed for a multi-party system and a non-ethnic government.

Ndadaye was assassinated during another attempted coup after only three months in office, leading to a series of retaliatory killings that culminated in the Burundian Civil War.

In November 2020, he was sentenced to life in prison in absentia by a Burundinan court for his suspected role in the 1993 coup attempt that assassinated Ndadaye.

[3] He enlisted as an officer the Burundian Army and studied at the Royal Military Academy in Brussels, Belgium, rising to the rank of major.

[4] Academically, Buyoya studied social sciences, examined armoured cavalry, and defended a thesis concerning the Algerian National Liberation Front.

In early October he appointed a mixed government of both civilian and military figures and awarded himself the post of Minister of National Defence.

[7] Some human rights groups suspected Buyoya of supporting the putschists,[8] while several soldiers who participated accused him of helping plan the coup.

On 25 July 1996, with strong support and backup from the army, Buyoya returned to power in a military coup, ousting interim President Ntibantunganya who had been contested by the population due to his failure to stop killings perpetrated by rebels.

[14][15][16] In his 2007 book From Bloodshed to Hope in Burundi, the former US Ambassador Robert Krueger accuses Buyoya of orchestrating the 1993 putsch that led to the murder of President Ndadaye.

[2] On 19 October 2020 the Supreme Court of Burundi sentenced Buyoya in absentia to life in prison for the murder of Ndadaye in 1993.