The development of Lezajsk was slow, due to numerous and devastating Tatar and Wallachian raids, which took place in 1498, 1500, 1509, 1519 and 1524. Following these raids, Polish kings granted several privileges to the looted town, and finally, on September 23, 1524 in Lwow, King Zygmunt Stary decided to move Lezajsk to a new location, which was easier to defend. The town was moved some 5 kilometers south-west, and its new name was Lezajsk Zygmuntowski. During the reign of Zygmunt August, Lezajsk prospered due to protection of its starosta, Krzysztof Szydlowiecki (Odrowaz coat of arms), who was Crown Chancellor. In 1608, Bernadine monks from nearby Przeworsk were brought to Lezajsk by Bishop of Przemyśl, Maciej Pstrokonski, and two years later, first brick church was built. In 1624 Lezajsk was looted and burned by Crimean Tatars, Swedish invasion of Poland (1655 - 1660) brought more destruction.
Following the first partition of Poland (1772), Lezajsk was annexed by the Habsburg Empire, and remained in Austrian Galicia until November 1918. In 1809, the town was captured by the Duchy of Warsaw, but soon afterwards, it was retaken by Austrians. In 1896-1900, a rail line connecting Lezajsk with Przeworsk and Rozwadow was completed. The town suffered during World War One, as Austro-Hungarian and Russian armies fought here in 1914 and 1915. Lezajsk was occupied by Russians between November 1914 and May 1915.
Prof. Janusz Dolny, b. December 3, 1927, a Polish pianist and composer, was born in Kurylówka, a village in the province of Leżajsk; He studied music at Konserwatorium Krakowskie im. Witolda Lutoslawskiego in Kraków and lives in Kraków.
Count Jan Potocki (1761–1815), capitan, engineer of the Crown Army, ethnologist, Egyptologist, linguist, and author.