He was a maritime explorer of Alaska and the Pacific Ocean, and served briefly in 1817-1818 as the second Chief Manager of the Russian-American Company.

Along with a group of fellow junior servicemen, he joined the British Royal Navy in 1802 on board HMS Argus.

[2] Departing on 20 October 1806 from Kronstadt, Neva began to cross the Atlantic Ocean to the south, to go around the continent of Africa and sail East.

His circumnavigation was recognized by Russian authorities at St. Petersburg, as he was promoted to captain lieutenant and awarded the Order of St. Vladimir 4th class.

[3] He served as chairman of the Admiralty of Irkutsk from 1812 to 1815, in which capacity Hagemeister was responsible for building the first ships to cross Lake Baikal.

Before examining Baranov's financial records, Hagemeister traveled to northern California to formalize relations with the Kashia Pomo people.

[4] Hagemeister took over, changing the methods of payment to the promyslenniki workers, by giving currency for salaries and abandoning the share system in favor of provisions.

[7] This policy was contained in the Ukase of 1821, a decree from the Imperial Government that extended Russian land claims to northern California and banned all non-Russian European merchants from the area.

His diaries are composed in several European languages, including German, Russian, French, Portuguese, English and Spanish.