Eugene Roland Kellersberger was born in Cypress Mill, Texas on 6 August 1888 to Helene Matern and Julius Rudolph Kellersberger. He attended Whitis Academy in Austin, Texas, graduated from the University of Texas at Austin in 1911 with a B.A. degree, and earned his M.D. in 1915 at Washington University Medical School in St. Louis, Missouri. In 1912, Kellersberger married Edna Helena Bosché of Austin, Texas.
In 1916, the Kellersbergers sailed for the Belgian Congo in Africa as a missionary couple for the Presbyterian Church in the United States' Executive Committee of Foreign Missions. Their two daughters, Winifred and Cornelia, were born in 1917 and 1921, respectively. Edna Kellersberger spent one full term, from 1916 to 1919, on the mission field. In June 1921, shortly after returning to the Congo from their first furlough, she contracted African sleeping sickness. Following successful medical treatment in London, she and her husband returned to the United States in 1922 and were reunited with their daughters. In 1923, Dr. Kellersberger returned to the Congo mission field alone. In November of the same year, he received word that his wife had been killed at her father's Texas ranch. Following Mrs. Kellersberger's death, the hospital at Bibanga, Belgian Congo, was named the Edna Kellersberger Memorial Hospital.
During Dr. Kellersberger's medical missionary service to the American Presbyterian Congo Mission (APCM), he founded the Bibanga Medical School and Hospital and the Bibanga Agricultural Colony (leprosarium). He also served as Medical Secretary for the Congo Protestant Council (1936-1940), and was a member of the Royal Commission for the Protection of Natives. His work in the Congo included pioneering research in the treatment of African sleeping sickness.
Dr. Kellersberger remarried to Julia Lake Skinner in 1930 and together they served as missionaries to the APCM until 1940, when he was elected General Secretary of the American Mission to Lepers (in 1950 name changed to American Leprosy Missions). With headquarters in New York City, this interdenominational agency provided assistance to various Protestant mission boards in their medical and spiritual ministries to leprosy patients. His official service of induction as General Secretary took place in March 1941 in New York City. Often accompanied by his wife, who served as promotional secretary for the agency, Dr. Kellersberger visited leprosy colonies and hospitals throughout the world, raising funds and awareness about the disease. He attended several World Leprosy Congresses as the official representative of the United States government. After his retirement from the American Leprosy Missions in 1953, Dr. Kellersberger continued to lecture and write about leprosy from his home in Melbourne, Florida until his death on 28 January 1966.