Hryhorii was born into a peasant family in the village of Huliaipole on 24 January 1886 to Ivan Rodionovych Mikhnenko and Evdokiia Matveevna Perederyi.

[1] When his brother Nestor Makhno was arrested for participating in the group, Hryhorii visited him in prison and told him of the death of their comrade Oleksandr Semenyuta.

[4] When the Insurgents separated from the Red Army and began their retreat westward, Hryhorii joined the small detachment around his brother Nestor.

[5] For some time Hryhorii served as the chief of staff of the united rebel troops of Nestor Makhno and Nykyfor Hryhoriv,[6] then as a member of the Military Revolutionary Council (VRS).

[10] After receiving news of his brother's death, an enraged Nestor responded by massacring the wounded White officers that the insurgents had captured.