However, Władysław Odonic took care properly for the upbringing of his offspring, evidenced by the fact that Bolesław, like his older brother Przemysł I, was able to read and write Latin.

In 1244, Bolesław supported his brother in a conflict between the local nobility and the clergy led by the Bishop of Poznań Bogufał II for the privileges their father had granted shortly before his death.

On 24 April 1245 Przemysł I acknowledged Boleslaw's coming of age by knighting him during a solemn Mass in honor of St. Adalbert of Prague in Gniezno, celebrated by Archbishop Pełka Liz.

This decision was not recognized by Władysław Odonic's sons, but eventually they reconciled and even signed an alliance with the Kuyavian Duke, which effectively ended any attempt to change the ownership of the disputed land.

The final reconciliation between the brothers occurred in May of that year at a meeting in Pogorzelica near Giecz, where thanks to the mediation of Pełka, the Archbishop of Gniezno Bolesław recovered his Duchy of Kalisz-Gniezno.

On 8 May 1254, Bolesław took part in the national Congress of Piast princes at Kraków on the occasion of the canonization of St. Stanislaus, where they decided to form a coalition against Swantopolk II, Duke of Pomerania.

This union resulted in a permanent bond between Bolesław and Hungary, reflected in the assistance given in the conflict with Bohemia after the extinction of the House of Babenberg.

For Bolesław, this alliance cost him the devastation of Greater Poland during the winter of 1267-1268 by troops of King Ottokar II of Bohemia during his return from an expedition against the Prussians.

The Duke of Greater Poland quickly took Radziejów, Kruszwica and the castle in Bydgoszcz; however, rapid action by Ziemomysł regained temporary control of this lands.

Bolesław retained the Duchy until 1273, when he gave it to Ziemomysł's brother Leszek II the Black, except for Radziejów and Kruszwica, which remained in Greater Poland.

As a dowry, Brandenburg received the castellany of Santok (but without the important main city) with the consent of a wiec reunited in Greater Poland, which took place on 1 July 1260 in Poznań.

The invasion of Międzyrzecz launched by the Margraves of Brandenburg was successfully repulsed by Bolesław, who in December 1269 could advance to Lubusz and in addition, during this expedition burned several fortresses, included the one newly built in Sulęcin.

For this reason, in the spring of 1271 Bolesław organized a major military expedition against Santok and Neumark, ravaging this land terribly, but he could not recover the lost domains.

Although nominal leadership of the troops was given by Bolesław to his young nephew Przemysł II, the expedition was actually headed by experienced commanders such as the voivode of Poznań, Przedpełk Łodzia, and the castellan of Kalisz Janek.

The last campaign against Brandenburg during Bolesław's lifetime took in the summer of 1278, when Greater Poland troops advanced to Myślibórz and eventually recovered Santok.

To bind Przemysł II with his politics, Bolesław arranged the marriage of his nephew with Ludgarda, daughter of Henry I the Pilgrim, Lord of Mecklenburg.