Career
Kyoseivanov came to power on 23 November 1935 after a period in which the country had had three Prime Ministers in quick succession. He went on to become the longest-serving Prime Minister since Andrey Lyapchev and throughout the period of his administration he also held the post of Foreign Minister. The government oversaw the trials of the instigators of the 1934 military coup and also concluded pacts with Yugoslavia and Greece as Nazi Germany undertook a policy of economic isolation of the Balkans.
His government also oversaw a policy of rearmament after a treaty concluded with Ioannis Metaxas overturned the military clauses of the Treaty of Neuilly-sur-Seine and the Treaty of Lausanne.
In 1940 he became ambassador to Switzerland where he remained after the 1944 coup in Bulgaria.