Fr. Dennis O'Mara, SSC was born on November 18, 1936, in Chicago, IL, the second child of Ellen and Francis O'Mara who lived in Queen of Angels parish. He attended St. Margaret Mary grade school. He received his high school education at St. Columban's Minor Seminary, Silver Creek NY. He continued in Columban formation studies and was ordained a priest on December 21, 1961, in the seminary chapel in Milton, MA.

After ordination, he did post-graduate studies in Rome, receiving a Ph.D. at the Gregorian University. By June of 1967 he was appointed to Australia to teach at the Columban seminary there. There he remained until returning to Chicago on vacation in February of 1978. In April of that year, he received an appointment to the missions, being sent to work in Chile. Before taking up work there he studied Spanish in Cochabamba, Bolivia. By January of 1979 he was working in the parish of Sta Luisa, Barrancas, near the port city of San Antonio. Dennis became active in the local prison and this led to his work with alcoholics.

Fr. O'Mara was socially conscious and was appalled by the repressive actions of the Pinochet regime. In October 1983 he was arrested, along with 19 other priests, religious and lay people after a demonstration against torture. In 1984 Fr. O'Mara was deported from Chile. After a stopover in Lima, where he was met by the Columban Director in Peru, he arrived home in Chicago.

Denny was appointed to the U.S. in March of 1985 and was sent to the Columban parish in Alamogordo, NM.

After the fall of Pinochet, Fr. O’Mara was able to pay a visit. He stepped once more on to Chilean soil on July 1, 1992 “It's great to be back, with the people being free and so much less tension in the air," he said. The Community of John XIII in Pedahuel, where he was working at the time of his arrest and expulsion, gave him a great welcome.

In the summer of 1992 Dennis was appointed to the Hispanic Apostolate in Immaculate Conception Parish in Grand Prairie, TX where he served until 1999. Later he became pastor of St. Philomena Parish in Chicago. This was followed by his work with fellow Columbans in El Paso, TX and across the border in Juarez, Mexico. In July 2017, he retired to the Columban House in Bristol, RI.

He was preceded in death by siblings Mary Ellen Zengler/Fitzgerald (Robert/Morgan), Thomas (Eileen) O’Mara, Patricia Mongoven, Maureen and Robert O’Mara

He was a kind and thoughtful soul and will be dearly missed by his brother, Stephen (Judith) O’Mara and a large number of cousins, nieces & nephews and his Columban community.

A Mass of Christian Burial will be held on Thursday, July 30, 10 AM at Columban Fathers Chapel, 65 Ferry Road. Burial will follow in St. Mary’s Cemetery.