The acting hetman was the governing authority in the Cossack Hetmanate temporarily substituted for the hetman. The acting hetman was appointed by the hetman himself or elected by the Council of Officers (starshyna), to perform the duties of the hetman when absent during military campaigns, foreign travels, or his incapacitation. As well as a temporary replacement if the hetman's office became vacant, because of death, abdication, or deposition. Sometimes acting hetmans were appointed by foreign leaders such as Ivan Bezpaly was appointed acting hetman by the Muscovite voivode of Belgorod.
Usually acting hetman was chosen out of the General Officer Staff and more than often it was a General Quartermaster, a leader of the staff. There were incidents when acting hetman was chosen among colonels (a regional leaders) such as Yakym Somko.
Some notable acting hetmans who held this form of the office were Yakym Somko who was appointed by Yurii Khmelnytsky in 1660 until his execution in 1663, Demian Mnohohrishny was appointed by Petro Doroshenko from 1668-1669 until becoming full-time hetman, and Pavlo Polubotok who served as acting hetman in 1722, till 1724.