Jack (John Patrick) O’Brien was born to parents Thomas J. and Mary (nee Hegarty) O’Brien on December 1st 1918 in Donamon, Co Roscommon
Thomas and Mary had four children:
Jack, who joined the Society of St Columban and was killed at the Massacre at Taejon
Joe, who died of meningitis as a young boy.
Máirín, who joined the Irish Sisters of Charity and was given the name Sr Mary Dolores.
Vincent, who joined the Society of St Columban and worked in the Philippines..

Their father, Thomas O’Brien father was a Station Master in Donamon when Jack was born but moved as was required by his job.

Jack attended Kilalla N.S. from 1924 to 1925 and Ballinrobe N.S. from 1925 to 1931 By the time he was ready for secondary education the family had moved to Ballaghadereen so he attended St Nathy’s College in Ballaghadereen, Co Roscommon (1931 – 1936).

He had, at a young age, made up his mind to become a missionary and his chosen field was the Far East. He went to Dalgan in 1936 and was ordained in 1942.

On his Ordination Day, December 21st, 1942, Father John O’Brien gives his blessing to the ordaining prelate, His Grace, the Most Rev. Dr D’Alton Archbishop of Armagh, at that time coadjutor Bishop of Meath.

Due to World War 11 he was unable to go on the overseas mission so he served as a chaplain to the British Army and was attached to the Royal Ulster Rifles. In November 1944 he wrote “My battalion has been in action almost continually since D-Day. They have been through the heaviest fighting in France and also in Holland. Our casualties have been very heavy indeed and I need not tell you that there are very few of the original lot left.

Even before the surrender of German forces in May 1945 some chaplains, including John, were asked to continue to serve. By October his battalion was in Egypt and in January 1946 in Palestine. It wasn’t until 31 May 1948 that Fr Jeremiah Dennehy, the Superior General, appointed him to Moppo (Mokpo) Zendra-Nan-Do, Korea. He left home on 20th February 1949. (Extract from Columban Martyrs by Neil Collins)

He worked in Mokpo parish with Father Tommie Cusack and Father Pat Lohan.

On the 25th of June 1950 the Korean War broke out when the North Korean Army crossed the 38th Parallel into South Korea. Those in the extreme south of South Korea had no great fears. They believed that within a few weeks the conflict would end, especially since United States troops were getting into it.

However, on the 17th of July the U.S. Command sent a young man named McDonnell to inform the Columban Fathers that they could no longer defend the Kwangju area and they offered the priests safe passage to Pusan in American convoys and transferred some to an American Minesweeper.

Many priests escaped the advancing tidal wave of Communist soldiers. However, Monsignor Brennan the Prefect of Kwangju, Father Tommie Cusack, Parish Priest of Mokpo and Father Jack O’Brien who had only been in Korea for a few months, took the unanimous decision to remain with their parishioners. Jack O’Brien of his own free will did not hesitate to remain in the Battlefield he had chosen and to die for his beliefs and ideals.

In 1956, in his book “One Front Across the World”, Douglas Hyde wrote, "'The blood of Christians is a seed.' How true Tertullian’s words prove in Korea today. I think of my friend Fr Jack O’Brien, martyred at Taejon, and other Irish priests mentioned in this book, and hosts of faithful Christian Koreans, and I praise God for the harvest their death has brought forth."

Father Jack O’Brien was 31 years old when he was killed.

Please click here to read about the Captivity and Deaths of Monsignor Pat Brennan, Fr Tommie Cusack, and Fr Jack O’Brien.