[2] On December 19, 1962, Clark was ordained to the priesthood in Rome by Martin O'Connor in the Sacro Cuore di Cristo Re Basilica for the Diocese of Albany in New York.
[3] He was consecrated in Rome on May 27, 1979, by John Paul II himself, with Archbishop Duraisamy Lourdusamy and Cardinal Eduardo Somalo serving as co-consecrators, at St. Peter's Basilica.
[3] In 1986, Cardinal Josef Ratzinger ordered Clark to withdraw his imprimatur, or church approval, from a sex education manual written by a priest in his parish.
[4] On March 12, 1986, Clark defended one of his priests, the theologian Father Charles Curran, from criticism by Vatican officials for his stands on birth control, abortion rights for women, homosexuality, and divorce.
[7] In 2004, the diocese was deemed to be in "full compliance" with the US Conference of Catholic Bishops (USCCB) charter for the protection of children and young people.
[8] Clark presided over the unpopular closing of many of Rochester's parochial schools and parishes, pledging to complete the "re-sizing" of the diocese prior to his retirement in 2012.
He admitted sending Eugene Emo, a priest later convicted of sexual abuse of a minor, to a treatment facility, then reassigning him to another parish.