He served as the Governor-General of Finland from August 18, 1904 to November 18, 1905. His predecessor Nikolai Ivanovich Bobrikov was assassinated in June 1904. His mother was the Romanian-born princess Mărioara Sturdza, daughter of Alexandru Sturdza.
His father was Prince Mikhail Aleksandrovich Obolensky (1821–1886).
His term of office saw revolutionary turmoil in both Russia and the Grand Duchy of Finland. The Russian revolution of 1905 resulted in a general strike in Finland and the replacement of the feudal Diet of Finland with the modern Parliament of Finland.
He was murdered by revolutionaries in Saint St. Petersburg.