Michael J. Matt is the editor of The Remnant, the traditionalist Catholic newspaper founded in 1967 by his father, Walter Matt. The paper says he has edited it since 1994, founded its video arm, Remnant TV, and hosts its programme The Remnant Underground (The Remnant; Wikipedia). He co-founded and emcees the annual Catholic Identity Conference (Catholic Identity Conference), whose 2021 edition took the theme "Holy War: The Kingship of Christ vs. the Great Reset" (The Fatima Center). The 2026 conference met near Pittsburgh on 2–4 October with Bishop Athanasius Schneider as keynote speaker (InfoVaticana; The Remnant).
In 2000 he co-wrote We Resist You to the Face with Atila Sinke Guimarães, John Vennari and Marian Horvat, presented by its publisher as a public resistance to teachings of the Council and of John Paul II that the authors judged contrary to the Magisterium (Tradition in Action). In 2019 he promoted the slogan "Unite the Clans", urging traditionalists not to attack allies for insufficient purity; Fr. John Zuhlsdorf backed the call (wdtprs.com), and OnePeterFive later named the phrase as a basis of its editorial stance (OnePeterFive).
Throughout Francis's pontificate Matt criticised the pope, for instance presenting him in December 2021 as turning against Catholics attached to the traditional liturgy and sacraments (The Remnant) and joining the editors of Catholic Family News in a public accusation of the pope (OnePeterFive). He has been criticised from several directions: an essay in Catholic Answers Magazine argued that he and Christopher Ferrara attribute to opponents positions they do not hold (Catholic Answers), while the sedevacantist site Novus Ordo Watch faults him for continuing to recognise a pope he accused of grave error (Novus Ordo Watch).
After the 2025 conclave he published an open letter to Leo XIV arguing that traditional Catholics would be the new pope's strongest allies if he led the Church back to tradition (The Remnant). He later counselled patience, pointing to the permission given for Cardinal Raymond Burke to celebrate the traditional Mass in St. Peter's Basilica (The Remnant). In 2026 he criticised Leo more directly: in August he called a papal warning against retreating into religious certainties Leo's "biggest blunder" (The Remnant), and in September he linked Leo's catechesis on Gaudium et spes to a wider critique of the Second Vatican Council (The Remnant). See papal-critique and resistance media.