[1] Rudnev was born in Dünamünde, Governorate of Livonia of the Russian Empire (now part of Riga, Latvia), where his father was a naval officer and a hero of the Russo-Turkish War.

His ancestors were local nobility from Tula, Russia, one of whom was also a naval officer who had been decorated by Tsar Peter the Great for valor at the Battle of Azov.

In 1893, Rudnev was promoted to junior captain and became executive officer on the battleship Imperator Nikolai I, the flagship of Admiral Stepan Makarov's Mediterranean Squadron.

In December 1897, Rudnev became commander of the gunboat Gremyaschi, on which he made his first independent voyage round the world, departing March 1, 1898 and returning safely to Russia on May 15, 1899.

[1] During this time, he oversaw extensive upgrade works to dredge the inner roads, rebuild and extend the dry-dock, electrification and strengthen coastal defense.

On the morning of February 9, 1904, he received an ultimatum from Imperial Japanese Navy Admiral Uryū Sotokichi demanding that he leave the protection of the port by noon, or be attacked (which would have been a violation of Korean neutrality and international law).

Although the Battle of Chemulpo Bay was a decisive defeat for Russia, Rudnev was awarded the Order of St. George (4th class) for heroism and promoted to adjutant.

In autumn 1905, however, his good fortune began to wane with his failure to prevent his crew from holding a meeting to protest the tsar's October Manifesto.

After the war, in 1907, Japanese Emperor Meiji awarded Rudnev the Order of the Rising Sun, (2nd class), the first Russian to be so honored,[2] and an unprecedented recognition of an enemy commander.