Donald Eugene Brennan was born December 20, 1927 in Chicago, IL to Walter J. and Norrine Brennan. He was Baptized January 1, 1928 at St. Gall Church, Chicago. He received the Sacrament of Confirmation in June, 1938 at St. Adrian Church, Chicago.

After attending St. Adrian School until Grade 4, he completed his elementary education at Bishop Quarter Military School, Oak Park, IL, graduating in 1941. In the Fall of that year, Donald entered the minor seminary program at Augustinian Academy, Staten Island, NY. When St. Monica Seminary, Oconomowoc, WI, opened in 1942, he joined other students from the Midwest there for two years. He returned for his Senior Year to Augustinian Academy, where he earned his high school diploma in 1945.

He was received into the Augustinian Novitiate September 8, 1945. He professed Simple Vows September 10, 1945 and Solemn Vows September 10, 1949. He was ordained a Priest December 21, 1953.

Following his profession of vows, Donald studied at Villanova Univesity, Villanova, PA, where he earned a B.A. in Philosophy in 1950. He followed the program of theological studies at Augustinian College, Washington, D.C., from 1950 to 1954. He earned an M.Ed. in Guidance from DePaul University, Chicago, in 1964 and an M.A. in Theology from St. Xavier College, Chicago, in 1968.

He served as a teacher in several Augustinian secondary schools; Austin Catholic High School, Detroit, MI (1954-1959), Mendel Catholic High School, Chicago (1959-1961 and 1972-1975), St. Rita High School, Chicago (1961-1968) and Augustinian Academy, St. Louis, MO (1968-1972).

In 1975 and 1976 Father Brennan served briefly in the Peruvian missions. Upon his return, he was assigned to St. Augustine Seminary, Holland, MI, while participating in the Pastoral Institute at Notre Dame University, Notre Dame, IN.

He was named Pastor of St. Joseph Parish, Pekin, IL in 1977, where he also served as Prior of the community. In 1983, he was named the Prior at St. Clare of Montefalco Parish, Grosse Pointe Park, MI.

Father Brennan was appointed Pastor of St. Rita Parish, Racine, WI in 1984. In 1996,he was named Pastor of St. Thomas Aquinas Parish, Pilot Point, TX and a member of the St. Mary Center House community, Gainesville, TX. Following his retierement as Pastor in 2002, he continued as part of that Augustinian community while providing pastoral ministry as needed. He was named Prior of the Augustinian community at St. Mary in 2002. He served in this office until 2008.

In 2008 Father Brennan was assigned to Cascia Hall Monastery, Tulsa, OK. He volunteered his assistance in Cascia Hall School as his health and strength permitted.

A Mass of Christian Burial will be Tuesday, June 29, 2010 at 2:00 p.m., at St. Rita Chapel at Cascia Hall, Tulsa. Interment will be at Calvary Cemetery, Tulsa.