Details about his childhood are unknown. Being a starost (governor) of Wschowa, he became a deputy to the Lublin Seym in 1703 but, like other deputies from Poznań and Kalisz, he was accused of Swedish sympathies and removed from the chamber of deputies, which he protested against. He was engaged in supporting Jakub Sobieski as a candidate for the king of Poland. When it turned out that this candidate to the crown did not stand a chance, Radzewski joined the supporters of Stanisław Leszczyński, becoming one of his leaders in Wielkopolska (Greater Poland). Radzewski strengthened his position after Leszczyński’s election as king in 1705. When Augustus II regained power, Radzewski did not suffer any major repressions, not counting the loss of the royal rank of chorąży granted to him by King Stanisław. He participated in successive Seyms and continued his opposition activities against Augustus II Wettin, which he limited in the 1720s. The brief return of Stanisław Leszczyński to power in 1733, however, was largely credited to Radzewski, who became the speaker at the Electing Seym. Radzewski and the king found shelter in Gdańsk, but after its surrender Radzewski ended up in Russian captivity. He was imprisoned, probably until 1735 or even 1736, following his refusal to recognise the power of August III. In 1741, he tried to persuade the Swedes to cooperate and support the anti-Russian Confederation that Radzewski wanted to establish. When these plans failed, Radzewski got involved in political journalism. Among others, he wrote a reformist-oriented work entitled Kwestyje politycznie obojętne… (1743). He used the name of Franciszek Poklatecki as his pseudonym. He died on 5 May 1748.