He attended the College of St. Thomas (St. Paul) from 1938 to 1941, graduating Summa Cum Laude in 1941 and was again valedictorian of his class, earning a baccalaureate degree with majors in classics and history.
When in 1965 he accepted the invitation of the Reverend Martin Luther King Jr. to participate in the funeral in Selma of a murdered civil rights defender, conflicts arose with his fellow bishops.
[citation needed] His most devastating reproach to his superiors, however, came in the summer of 1968, after being called to moderate a television documentary, "The New American Catholic," broadcast by NBC.
The program examined the effects of the Second Vatican Council, convened in 1962 by Pope John XXIII to "renew the Church and adapt the norm of ecclesiastical law to the needs and thoughts of our time".
In his memoir, Monsignor Shannon wrote: "My great pride in being an American Catholic bishop has suffered a severe blow that day and has never recovered".
[citation needed] In that same fateful summer, Pope Paul VI in the encyclical Humanae Vitae upheld the Church's position opposing artificial methods of birth control.
[2][3][4][5] The resignation was a shock to the progressive wing of the Catholic Church in the United States and caused protests and outrage by his supporters, both priests and lay people.
After marriage, he returned to law school and began a new career in numerous non-profit organizations including the General Mills Foundation.
Shannon remained a practicing Catholic and regularly attended the parish church of the Holy Name of Jesus in Medina.
[6] The funeral was held on September 5 in the parish church of the Holy Name of Jesus in Medina and concelebrated by sixty priests.