Schenck was born in Glen Ridge, New Jersey. He has an identical twin brother, Robert, with whom he was raised in Grand Island, New York. His father was born Jewish and his mother converted to Judaism. He and his brother attended Beth El Hebrew School in nearby Niagara Falls. Schenck was baptized in the evangelical and Anglican Christian tradition when he was 16 years old. He was married in 1977. While attending bible college, he was youth minister on Grand Island, New York, and an assistant pastor and pastor in the Town of Tonawanda, New York. Schenck founded the New Covenant Tabernacle Church in Tonawanda in 1982. Under his direction it grew to be one of the largest, most influential community churches in Western New York. After 12 years as Senior Pastor he stepped down and served as Minister of the Word until his resignation in 1994 and moved to Hampton Roads, Virginia.
Between 1989 and 1994 Schenck and his brother Robert, with Rev. Johnny Hunter and Dr. Karen Swallow Prior, led Project Rescue, a pro-life activist that was involved in public demonstrations, media, public policy advocacy, education and legal challenges.
After joining the Reformed Episcopal Church in 1994, he was vicar of a mission in Virginia Beach, Virginia and later rector of a parish in Catonsville, Maryland. Between 1994 and 1997 Schenck was executive vice president of the American Center for Law & Justice, a public interest law firm then headed by Deacon Keith Fournier and Attorney Jay Alan Sekulow. Robert moved to Washington, DC and later joined the Evangelical Church Alliance.
Until about 1994, the brothers had worked together, primarily in Buffalo, New York, but then Schenck moved to Virginia Beach, Virginia and joined the American Center for Law & Justice, a public-interest law firm. His brother Robert moved to Washington, D.C., where he founded Faith and Action.
In Schenck v. Pro-Choice Network of Western New York, Schenck's challenge to a court order prohibiting certain forms of sidewalk counseling went to the Supreme Court in 1996. The case was to decide details about restraining orders, in particular for protesters around abortion clinics. The Court held that the injunction provisions imposing "fixed buffer zone" limitations were constitutional, but the provisions imposing "floating buffer zones" violated the First Amendment. The Court voted 8-1 in Schenck's favor striking down the floating zones. The Court used that case to strike down similar restrictions in Colorado, Arizona and California.
In 1996 Schenck became Rector of the Cummins Memorial Church near Baltimore, Maryland. Schenck received awards from the Catholic Lawyers Guild, the Franciscan University of Steubenville, the Thomas More Society and the Maryland Right to Life.
Schenck graduated from the Luther Rice University with a B.A. in biblical studies in 1984. He stood his canonical examinations for ordination in the Reformed Episcopal Church at the Reformed Episcopal Seminary in 1995. Schenck received the Master of Arts in Theology from Catholic Distance University summa cum laude in 2005. In 2007, he received a Master Certificate in Executive Leadership from the Mendoza College of Business at the University of Notre Dame in Notre Dame, Indiana. In 2009, he completed certification with the Pastoral Provision in the Catholic Church at Immaculate Conception Seminary School of Theology at Seton Hall University in South Orange, NJ and received the Certificate of Preparation for Ordination from the theological faculty there. He studied liturgical theology with Msgr. Kevin Irwin at the Catholic University of America in Washington, DC. In 2012, he received the Doctor of Education degree in Applied Clinical Pastoral Practice from the Graduate Theological Foundation in Mishawaka, Indiana . He received the master's degree in bioethics from the Pope John Paul II Bioethics Institute at Holy Apostles College and Seminary in the Diocese of Norwich in Connecticut. In 2013, Schenck was awarded a certificate in Catholic Health Care Ethics from the National Catholic Bioethics Center in Philadelphia, Pennsylvania. His thesis was "The Incredible Shrinking Person: dementia and the personhood debate." He completed coursework in psychology and human personhood with the Institute for the Psychological Sciences at Divine Mercy University in the Diocese of Arlington (VA) where he gained the degree of Master of Science in Psychology.
He was granted the honorary degree of Doctor of Humane Letters by the Thomas More College of Liberal Arts in Merrimack, New Hampshire and Rome, Italy, and the Lifetime Achievement Award from the Franciscan University of Steubenville, OH.
Schenck is a member of the Kennedy Institute of Ethics at Georgetown University in Washington, D.C. where he completed the Master Course in bioethics taught by Edmund Pellegrino.
Schenck resigned as Rector of the old Reformed Episcopal Church of Catonsville, Maryland on November 7, 2003 and was received into full communion in the Roman Catholic Church on February 29, 2004 by Fr. Frank Pavone in the Roman Catholic Archdiocese of New York. He served as a Pastoral Associate in Priests for Life from 2004–2007 conducting missions, institutes and "parish weekends", became a founding member of the Missionaries of the Gospel of Life (MEV) and was seated on the council, was the National Representative of Catholics United for Life and was appointed Director of the Office of Respect Life Activities by Bishop Kevin C. Rhoades of the Diocese of Harrisburg in 2008. With Fr. Pavone, and his brother, the Rev. Robert Schenck, he founded the National Pro-Life Center, now known as the Center for Human Life and Dignity, on Capitol Hill in Washington, D.C. and is its chairman.
Schenck was ordained a priest for the Diocese of Harrisburg on the Feast of the Immaculate Heart of Mary (June 12, 2010) by Bishop Victor Galeone of the Diocese of St. Augustine as the Diocese of Harrisburg was sede vacante (without a bishop). While Schenck is married and has eight children, the ordination was made permissible under the Pastoral Provision created by Pope John Paul II for certain Protestant clergy received into full communion with the Catholic Church.
As of 2016 Schenck was a priest of the Diocese of Harrisburg, Director of the Respect Life Office, Director of Continuing Formation for Clergy and Director of the Deacon formation program. He is involved in ministry in Harrisburg, Annapolis, Maryland, Washington, DC and elsewhere in the United States.
Schenck is married to Rebecca "Becky" (Wald). They have eight children and two grandchildren.