He entered the Order in 1834 and was professor of philosophy and theology to his brethren at Issenheim, Louvain, Cologne, Bonn, Aix-la-Chapelle, and Maria Laach. In 1860 he took part in the Provincial Council of Cologne as a collaborator of Cardinal Geissel. In 1869–70 he attended the Vatican Council as theologian to the Apostolic Vicar of Bombay. There, in response to the pamphlets of Rauscher, Hefele, and Mayer, and to the *quaestio* of Ketteler, he published: *Animadversiones in 4 contra Romani Pontificis infallibilitatem editos libellos* (Rome 1870). Returning to teaching, he lectured in theology at the Faculty of Theology in Poitiers (1875–80) and at St-Hélier (1880–82); thereafter he devoted himself exclusively to his writings.
Of these, the principal work remains *Lehrbuch der Religion* (4 vols., Münster 1851–57; 7th ed., ibid. 1909–12, ed. Fr. J. Honteim; 8th ed., ibid. 1922–28, ed. Fr. A. Danefle), widely used and sought after, later supplemented by a *Geschichte der Religion* (2 vols., ibid. 1856; 7th ed., ibid. 1924, ed. Fr. O. Pfülf). Also his compendium: *Kurzgefasstes Handbuch der Religion* (ibid. 1871; Italian trans., Rome 1901), widely circulated and translated into several languages as a school text. Finally, he completed his Latin theological treatises: *De religione revelata* (Regensburg 1897); *De Ecclesia Christi* (ibid. 1897); *De Fide* (ibid. 1902, posthumous, ed. Fr. A. Lehmkuhl). Having moved from Cartesianism, still secular in character, to Scholasticism after thorough and long study, Wilmers is to be numbered, with Fr. J. Kleutgen, among the pioneers of Neo-Scholasticism, distinguished by clear, solid, and orderly exposition, albeit generally concise.