Until 1932, the settlement was a village named Zagożdżon. Its development was closely associated with Chemical Plant Pronit (Zakłady Tworzyw Sztucznych ZTS Pronit), founded in 1923 as State Manufacturer of Gunpowder and Explosives (Państwowa Wytwórnia Prochu i Materiałów Kruszących PWPiMK). Originally, it was an arms factory, which manufactured explosives, and its location was deliberate - next to the village of Zagożdżon, among the forests and swamps of the Kozienice Wilderness, away from main population centers, and along the strategic rail line Radom - Dęblin. After World War II, the Chemical Plant Pronit began manufacturing glue, plastic, as well as gramophone records.
In the interbellum period, Pionki prospered due to government contracts, as demand for explosives of its chemical plant was high. In 1925, a new rail station was opened, three years later - a post office. In 1929, overhead power line joined Pionki with Skarżysko-Kamienna, and a vocational high school was opened. Later on, a new police station was opened, and in 1937, the construction of a hospital was initiated. In 1939, Pionki was bombed by the Luftwaffe. In 1919 - 1939, and after the war, until 1975, Pionki belonged to Kielce Voivodeship. Punk rock band The Bill comes from Pionki.