Born in to a poor peasant family, Radoinov joined the Bulgarian Social Democratic Workers' Party (Narrow Socialists) while he was still a student.

[1] Radoinov who participated in the September Uprising fled to the Soviet Union through Turkey and was sentenced to death in absentia.

During his early residence in the USSR, Radoinov worked in an agricultural commune (later collective farm) names after Dimitar Blagoev in Poltava.

[2] By decision of the Foreign Bureau of the Central Committee of the Bulgarian Communist Party, Radoinov was sent to Bulgaria to organize a partisan resistance movement.

On June 25, Radoinov, along with 18 out of 27 defendants, was sentenced to death; the following day, the convicted were shot at the shooting range of the Reserve Officers' School in Sofia.