Jeningen entered the Society of Jesus on January 19, 1663, and became a successful popular missionary. He served at the shrine of Our Lady of Schönenberg, near Ellwangen in Swabia, which had been made famous by the Jesuits, and to which Jeningen, through the renown of his holiness, drew pilgrims from near and far. For many years he went forth on missions in the entire neighbouring country, his burning zeal achieving great results. He is remembered as the "Apostle of the Ries".