Kliment Voroshilov was born into a family of workers in the Yekaterinoslav governorate. He studied at the Zemstvo [local] school. Since 1896, he was employed as a worker, first at the Yuryevsky iron works. In 1903, he began working at the Hartmann steam locomotive plant in Lugansk. In 1903 Voroshilov joined the Russian Social Democratic Labour Party (RSDLP), the Bolshevik faction.

During the revolution of 1905–1907, he was the Chairman of the Lugansk Soviet of Workers’ Deputies. He led strikes and organized combat groups. In 1908–1917, he was engaged in the Party’s underground activities in Baku, Petrograd, Tsaritsyn, took part in the transportation of weapons and expropriations. Voroshilov was arrested several times and served a term in exile.

After the February Revolution of 1917, he headed the Lugansk Committee of the Bolsheviks and was the Chairman of the Duma and the Soviet of the city. After the October coup of 1917, he arrived in Petrograd, where he acted as the Petrograd Commissar for Civil Affairs; Chairman of the Committee of Petrograd Defense.

At the beginning of 1918, Voroshilov formed the 1st Lugansk Socialist Partisan Detachment, which defended Kharkiv against the German-Austrian troops. Separate detachments were reorganized into the 5th Ukraine Army under the command of Voroshilov. In July–August 1918, he commanded the Tsaritsyn group of troops. In August–September 1918, Voroshilov was a member of the Military Council of the North Caucasian Military District, in September–October 1918, he served as a member of the Revolutionary Military Council and the Assistant Commander of the Southern Front. In October–December 1918, he commanded the 10th Army. During this period, he became close to Joseph Stalin.

From November 1918 to January 1919, Voroshilov was a member of the Provisional Workers’ and Peasants’ Government of Ukraine, and from January to June 1919, he held a post of People’s Commissar of Internal Affairs of the Ukrainian SSR. He commanded the troops of the Kharkiv Military District, the 14th Army, and the internal Ukrainian front. He fought against the atamans Nikifor Grigoriev and Nestor Makhno. In October 1919, Voroshilov was appointed the Head of the 61st Rifle Division. From November 1919 to March 1921, he was a member of the Revolutionary Military Council of the 1st Cavalry Army under the command of Semyon Budyonny. In March 1921, Voroshilov led the group of the Bolshevik Party 10th Congress delegates that took part in the suppression of the Kronstadt rebellion.

In 1921–1924, he was a member of the South-Eastern Bureau of the Bolshevik Party Central Committee, the Commander of the North Caucasian Military District. In 1924–1925, Voroshilov served as the Commander of the Moscow Military District and was a member of the Revolutionary Military Council of the USSR. In 1925, he was appointed Deputy of Mikhail Frunze. After the death of Mikhail Frunze Voroshilov took over as People’s Commissar for Military and Naval Affairs. In 1925–1934, he was the Chairman of the Revolutionary Military Council of the USSR. In 1934–1940, Voroshilov was People’s Commissar of Defense of the USSR. Marshal of the Soviet Union (1935). He had held the highest government positions until 1960. Voroshilov died on December 2, 1969, in Moscow, and was buried in the Kremlin Wall Necropolis.