He was the seventh son of Bolesław IV of Warsaw and Barbara Aleksandrówna, a Lithuanian princess, (granddaughter of Vladimir Olgerdovich).

After the death of his father on 10 September 1454, Bolesław V and his siblings where place under the guardianship of their mother Barbara and Paweł Giżycki, Bishop of Płock.

In 1476 Bolesław V together with his brother Janusz II protested against the incorporation of Sochaczew (who was held by Anna of Oleśnica, widow of Władysław I, as a part of her Qprawa wdowia) to the Polish Kingdom by sending his troops to the disputed city.

The conflict for Sochaczew caused a temporary coolness in the relations between Bolesław V and the Polish Kingdom, which was expressed in his neutrality during the dispute between Nicolaus von Tüngen and King Casimir IV for the Bishopric of Warmia.

For unknown reasons, in 1484 Bolesław V resigned to the brothers parts of his domains: Konrad III received Zakroczym and Janusz II obtain Kamieniec, Błonie and Tarczyn.