According to Leger's Life of Archbishop Walsh, Peter had five brothers who also became Jesuits: Luke, Thomas, Michael, Daniel, and Walter.
Wadding studied humanities for seven years in Ireland, and then proceeded to Douai, where he graduates M.A., and subsequently doctor of both laws as well as of divinity.
He was admitted to the Company of Jesus on 24 October 1601 by Father Oliveræus, the provincial of Flanders, and commenced his novitiate at Tournai on 23 November 1601.
The disputations of both were published in Dutch after their death in one volume, entitled Twee brieven van den gelerden Peter Wading in sijn level Jesuit tot Antwerpen: d’eene, van den Regel des Geloofs’ d’andere,.
On 30 November 1632 Wadding completed a Brevis Refutatio Calumniarum quas Collegio Societatis Jesu Pragensi impegit scriptor famosi libelli cui titulus “Flagellum Jesuitarum”, præsertim in negotio Academiæ Pragnensis … Nissa, 1634, 4to.