In 1790 Kengelac enrolled at the theological seminary in the Alexander Nevsky Lavra (later called Saint Petersburg Theological Academy) and from there went to the University of Halle where his teachers included August Hermann Niemeyer, Johann Salomo Semler, Friedrich Albrecht Carl Gren, Johann August Nosselt and Johann Augustus Eberhard.He was awarded the doctor of laws at the inauguration ceremonies in 1794, together with a sword as a gift from Frederick William III of Prussia.