He is a Knight Grand Cross in the Equestrian Order of the Holy Sepulchre. He is the author of Heart of the Redeemer, published first by Trinity Publications and later by Ignatius Press, and Swords Around the Cross, The Nine Years War published under Christendom's publishing company, Christendom Press. He has filmed numerous programs for the Eternal Word Television Network (EWTN) including Saint Matthew: Evangelist of the Church; The Lenten Stational Churches of Rome; Saint John: Evangelist of the Heart of Christ; Glory of the Papacy; and Luke: Meek Scribe of Christ.
On November 30, 1988, Dr. O'Donnell made a tour of Castel Gandolfo and visited the ruins of the Emperor Tiberius under the papal residence. He learned that there Pope Pius XII had hidden thousands of Jews from Nazis during the Italian Occupation. His story is published in Margherita Marchione's defence of Pius XII.
He is an advisor to the Pontifical Council for the Family.
On May 31, 2007, Dr. O'Donnell was awarded the Distinguished Service Award from the Brent Society for outstanding contributions to Catholic education.
Dr. O’Donnell and his wife, Cathy, have nine children and live on their farm “Tir Connaill” in Stephens City, Virginia.