Historical Dictionary of the Russian Civil Wars, 1916-1926

Following the collapse of the Russian Army in late 1917, Udovichenko offered his services to the Ukrainian Central Rada and became head of the Operational Department of its General Staff. In January 1918, he became chief of staff of the Haidamak Kosh of Free Ukraine, with which he participated in the early stages of the Soviet–Ukrainian War. He was subsequently commander of the 3rd Haidamak Regiment (12 March–1 April 1918) and was then assistant head of the reconnaissance section of the operational department of the main staff of the Hetmanite Army. In late 1918, when the Ukrainian National Republic Directory overthrew Hetman P. P. Skoropadskii, Udovichenko joined its Ukrainian Army, in which he served as quartermaster general, first of the Chelm–Galician Front (from 26 December 1918) and then of the Right-Bank Front of the active army. From March 1919, he was chief of staff of the Gutsul′sk Kosh, and, from 6 June 1919, he was commander of the 16th Infantry Detachment of the Ukrainian Galician Army, which on 17 June 1919 became the 3rd Independent (Iron) Rifle Division, one of the most battle-hardened units of the Ukrainian Army. He distinguished himself in battle with this force during clashes at Vaniarka (near Odessa) with the Red Army group commanded by I. E. Iakir, but in October 1919 he fell ill with typhus and was captured by the Whites. He managed to escape from incarceration in Odessa and made his way to the Mogilev region, where he helped form the 5th Ukrainian Brigade, which later merged with the 4th Brigade to become the 2nd Rifle Division of the Ukrainian Army. Udovichenko then commanded this division (later renamed the 3rd Iron Division) until the remains of the Ukrainian Army were driven across the River Zbruch into Poland, in November 1920. There, he remained a close ally of Simon Petliura, supporting him in his clashes with the Ukrainian Army leadership and serving as inspector general of the army (from December 1920).

In emigration, Udovichenko settled in France, where he worked for a time as a miner. He was deeply involved in émigré politics, as head of the Brotherhood of Veterans of the Ukrainian National Republic and (from 1953) as head of the European Federation of Ukrainian Veterans Associations. He was also minister of war of the Ukrainian government-in-exile and (from 1954 to 1961) its deputy president. He died on his smallholding at Mentona, near Nice, where he was buried in the Russian (Staryi Zamok) cemetery.