The namiestnik exercised broad powers and could nominate candidates for most senior government posts (ministers, senators, judges of the High Tribunal, councilors of state, referendaries, as well as bishops and archbishops).

[b] In the event that the namiestnik were unable to exercise his office due to resignation or death, this function would be temporarily carried out by the president of the Council of State.

No namiestnik was named to replace him;[1] however, the role of namiestnik—viceroy of the former Congress Kingdom —passed to the Governor-General of Warsaw[2]—or, to be more specific, of the Warsaw Military District (Polish: Warszawski Okręg Wojskowy, Russian: Варшавский Военный Округ).

In particular, he controlled all the military forces in the region and oversaw the judicial systems (he could impose death sentences without trial).

Certainly from 1815 to 1831 the Congress Kingdom's military was controlled by Grand Duke Constantine Pavlovich of Russia, who de facto had more power than the namiestnik, Józef Zajączek.