Oboi reversed the benevolent policies of the Shunzhi Emperor, and vigorously pushed for clear reassertion of Manchu power over the Han Chinese.

Oboi's father Uici (衛齊) (d. 1634) was a senior military officer who was once garrison commander of the Manchu capital city Mukden while his paternal uncle Fiongdon was one of Nurhaci's most trusted generals.

Oboi officially started his military career in 1634 during the reign of Hong Taiji as a junior officer in the Banner's cavalry guard unit[4] in which capacity he distinguished himself many times in battle against Ming forces and was renowned for his personal bravery.

For this achievement he was promoted to the rank of a hereditary colonel third-class and bestowed the rare honorific title of "Baturu" (巴圖魯), which means "(brave) warrior" in Manchu.

After the death of Hong Taiji in 1643, Oboi supported the late ruler's eldest son Hooge over Dorgon during the ensuing succession crisis.

Despite Hooge's faction losing out to Dorgon's proposed compromised candidate, Hong Taiji's youngest son Fulin, Oboi continued to participate in military campaigns through the Qing dynasty's successful invasion of China in 1644.

[12] Despite his demotion, in 1648 and 1649 he took part in a campaign to extirpate Ming turncoat Jiang Xiang (姜瓖; d. 1649)––who had now turned against the Qing––from his base in Datong (Shaanxi, north China).

Just as Hooge was arrested and eventually died in prison, in 1648 Oboi was stripped of his rank and titles under a charge of claiming false victories in battle.

Oboi for his unswerving loyalty to his Banner and services to the Qing government was appointed a cabinet minister by Shunzhi Emperor, who also bestowed on him the title of Marquis of the First Rank.

In 1652 after Shunzhi successfully purged the court of the more powerful elements in Dorgon's faction, Oboi was elevated to a hereditary Duke of the Second Rank and more importantly appointed the commander of the imperial bodyguard (領侍衛內大臣), a job which doubled as the de facto police chief in the capital.

In this capacity Oboi acted as Shunzhi's much feared enforcer against Dorgon's old cohorts and helped to consolidate power to the throne and the Emperor's own "Upper Three Banners".

On his deathbed he appointed four "Executive Ministers" (輔政大臣) commonly referred to as regents[13] to "assist" his eight-year-old son Xuanye to govern the country until the young emperor reached the age of maturity at 16.

In the first years of the regency, the tension between the Yellow Banners faction and Suksaha was kept in check by the even handed Sonin and thus the four ministers maintained a relatively peaceful and efficient working relationship.

As Sonin gradually took more time off, Oboi monopolized decision making by dominating the indecisive Ebilun and worked to sideline Suksaha during policy discussions especially on issues concerning welfare of the Manchu Eight Banners.

By 1667 when Sonin realized he did not have long to live, he tried a last-ditch effort to restore balance to the regency and neutralize Oboi's rapidly expanding power clique by petitioning the then 14-year-old Kangxi Emperor to assume personal rule ahead of schedule.