Boris Ivanovich Anasenko was born to Ivan Anasenko (1810 - 1850) in the town of Ilyutin outside of Aleksandrgrad at an unknown date in 1841. His father, a soldier and survivor of the Russian Purges and the Exodus, was stationed in the town during the 1840's and Anasenko was born out of wedlock to an Inuit seamstress in the village, whose identity is largely unknown. When he turned 9, his father died of pneumonia and Anasenko was sent to Aleksandrgrad to live at a monastery, where he learned to read and write. Anasenko was reportedly socially awkward and was excoriated for being half-native, which many aristocratic children who studied at the monastery regarded as making him unclean.
With few prospects for employment as an orphan and with Inuit blood, Anasenko enlisted in the military at the age of seventeen in 1858.
Anasenko served in the military from 1858 until 1887, when he became Chancellor of Alaska. From his earliest enlistment, his superiors noted a keen desire for upward mobility and work ethic, and the military did not differentiate half-Inuits with pure-blooded Russians. Anasenko was stationed at Unalaska in 1861, where he eventually became a garrison leader in 1866. With the outbreak of the Aleutian Wars in 1869, Anasenko was right at the heart of the Alaskan campaigns, and made a name for himself in gallantry. Anasenko allegedly landed on a rebel-held island and pacified it single-handedly, an anecdote many have attributed to legend. However, his prowess as a commander was noted as he helped organize Alaskan defenses during numerous raids against Unalaska and he eventually was recalled to Sitka in 1871 to apprentice under then-General Karakov, one of the more powerful nobles in the Alaskan military.
Anasenko spent several years with Karakov helping pacify the East, and was stationed in Kialgory for several years. Coming from common roots, he was mocked by many nobles in Sitka, though Karakov was impressed by Anasenko's intellect and ability to make peace with Sioux leaders without significant conflict. Anasenko displayed tactical prowess during a major battle with the Crow people in modern-day Montana, and when Karakov became Grand Marshal was recommended for a post as a General. Anasenko advised Tsar Feodor as early as 1878 that a war with the United States was imminent within the next five to ten years, believing that the Americans were seeking any excuse to attack Alaska and seize the East, especially Kialgory. Anasenko oversaw the early version of the Army of the East at Evgenigrad in 1880 and 1881, before returning to Sitka to help design a potential offensive against the American Pacific Northwest in the event of a war. Due to Feodor's admiration of Anasenko's ideas for a quick, overwhelming strike at Sahalee, an idea that would eventually translate into the Battle of Burrard, Anasenko was given command of the Army of the Pacific in 1883 as it began to be formed, with the war with the United States only a year away. Anasenko's promotion angered many nobles in Alaska who had hoped to be given such a prestigious post, and those nobles worked to undermine Anasenko's war efforts throughout the ensuing conflict.