Robert was born in Bartow, Florida, the son of the Rev. C. Fred and Effie Frances Blackburn. Robert was the son of a Methodist minister, too. He married Mary Jeanne Everett 16 November 1943. They had three children: Jeanne Marie, Robert McGrady, Jr., and Frances Lucile. Robert, Jr. became the fourth generation of the family to enter Ordained Ministry. Mary Jeanne died 22 May 1977 after a long illness. On 9 September 1978 Bishop Blackburn married Jewell Haddock of Jacksonville, whom he had known for several years. After the Bishop's retirement, they moved to Jacksonville.
Robert was ordained Deacon in 1943 by Bishop Arthur James Moore. Rev. Blackburn was appointed to Boca Grande, Florida. Subsequently, he served the following Methodist churches in the Florida Annual Conference: First Church, Orlando ; Mount Dora; Trinity, DeLand; First Church, Jacksonville; and again First Church, Orlando. Altogether, he served as a Pastor for twenty-nine years, a tenure interrupted only by his service as a U.S. Army Chaplain during World War II, 1944–46. Rev. Blackburn was very active in conference affairs throughout his pastoral ministry, as well. He was considered an expert on financial matters. He was also elected a delegate to General and Jurisdictional Conferences between 1964 and 1972.
Episcopal ministry
The Southeastern Jurisdictional Conference of the U.M. Church elected Robert M. Blackburn to the Episcopacy in 1972. He was assigned to the Raleigh Episcopal Area, where he served for eight years. In 1980 he was assigned to the Richmond Area, where he served until retirement in 1988. During his final year of service, under his leadership the VirginiaAnnual Conference raised $19,400,000 for New Church Development. This was the largest sum ever raised by an Annual Conference in a one-year campaign to that date. Bishop Blackburn also served on several U.M. General Church Agencies: the General Council on Finance and Administration, the General Board of Higher Education and Ministry, the General Board of Church and Society, and the General Commission on the Status and Role of Women. He also served as a Trustee for more than a half-dozen U.M. institutions of higher education. Bishop Blackburn also represented the UnitedMethodist Church at the BritishMethodist Conference in Sheffield, England in 1980. He represented the U.M. Council of Bishops at the European U.M. Conference in Austria in 1984, as well.
Bishop Joseph Yeakel of Smithsburg, Maryland, remembered Bishop Blackburn as one of the "unsung heroes of the Church," a leader who was committed to serving his episcopal area. Both men became Bishops in 1972 and forged a bond through that common experience:
