Thomas was born to a Catholic home to loving and caring Christian parents in the city of San Francisco, California. Although his mother, Frances Sinclair, was a Baptist when she first met Thomas Michael Geraty in Lathrop, California, on a nursing case of a neighbor of his, he persuaded her to study the Catholic teachings, which she did. She could not conscientiously accept their beliefs, however, because she had been told by the Catholic priest that as a Catholic she could not daily read her Protestant Bible. So she decided to return to the Baptist Church.

Thomas and his four siblings, Gertrude, Marcella, Joseph, and Jean, all early were christened in the nearby St. Monica’s Catholic Church. But God, through providential circumstances, led the mother to the Seventh-day Adventist Church, and the daily morning and evening worships which she conducted helped keep the children with her.

Because of the father’s insistence, Thomas attended public school for eight and one-half years. He was baptized into the SDA Church and then went to the oldest high school in California, to the S.F.SDA Junior Academy, deciding themselves not to study linger the classroom instruction in organic evolution and Greek mythology.

After one year and a half in San Francisco, they continued their studies at Golden Gate Academy, where they daily commuted by street car, ferry, and electric train for one and one-half hours each way. Thomas then took his undergraduate work at Pacific Union College, where in his senior year he became interested in Hazel Mae McVicker, a classmate. She had promised the Education Department that she would be an elementary supervisor for the college upon her graduation, so she felt obligated to teach at PUC for at least the next school year. They married in the summer of 1938.

Geraty taught grades 7 and 8 in Berkeley from 1937 to 1939, when he was invited to be the Bible teacher at Mountain View Union Academy. Before that year was over, he was invited to join the staff at the Pacific Press Publishing Association, but declined. Then came the call from the General Conference Mission Board for the Geratys to go to Lanchou in Kansu, China. With a four-month-old son, Lawrence Thomas, they sailed from San Francisco on the Japanese ship, the Asama Maru, which terminated its voyage in Yokohama, Japan, The Geratys stayed with another PUC classmate, William Guthrie and his wife, who were in Tokyo, for one week until they transshipped on the Nitta Maru, bound for Shanghai via Kobe and the Inland Sea. Upon our arrival in Shanghai with Harry and Alice Morse, the China Division officers immediately sent the Geraty family to the Shanghai Sanitarium and Hospital for study of the Chinese language with five other young couples : Charles and Dolly Wittschiebe, Doyle and Paulene Barnett, H. Carl and Eva Currie, Ilah and Grace Stonebrook, and Arthur and Ruth Mazat.

The Chinese nurses in the Sanitarium and Hospital received pediatric nursing credit caring for little Larry while his parents were in language study. After some three or four weeks of intensive study, the secretary of the Division, S L. Frost, contacted the group with the explosive news that they should consider one of three options: to return to the United States, to join the Division staff and their families in the Philippines, or to evacuate to Burma. War clouds on the international scene appeared imminent. Japan, Italy, and Germany now constituted the Axis Powers. The six couples recommended Burma, and the China Division arranged for them to travel by coastal steamer in three contingents, to be followed shortly with four Chinese language teachers and their families. All six couples were at Kalaw, the hill station for the Burma Union Mission and studied Mandarin diligently as a foreign language with no opportunity to use it outside of classes. Shan and Burmese were spoken locally. All went well until 1942, when Japan bombed Honolulu, Manila, and Singapore! Imperial Japan promised to give Rangoon, the capital of Burma, a “Merry Christmas! “  And they did with heavy bombing, and loss of life and property. This meant another evacuation for the six families and their Chinese teachers and families. Preparations soon were made to disburse the personnel, most going by loaded trucks over the circuitous Burma Road and some flying by plane from Lashio into Kunming, Yunnan, and on to Chungking, Szechuan, which became the war-time capital of China. The Ta Chi Ko compound in Chungking became for the Adventists the war-time office for the Free China 
Division, while Hsu Hua and S. J. Lee valiantly served at the Shanghai headquarters on Ning Kuo Road. Upon the arrival of the evacuees from Burma, the Chungking officers convened an annual meeting of the China Division Executive committee, at which time they reassigned the six couples to new responsibilities in unoccupied China during World War II.

The Geratys were asked to join the faculty and staff of the China Training Institute at Ta Pa, 26 Chinese miles west from Chungking, up the Chia Ling River. As Business Manager, Bible, and English teachers, Thomas and Hazel served under primitive conditions for the five years until they went on furlough. He was ordained in 1944, and along with his school work, Thomas conducted public evangelistic meetings in the city of Chungking. During that time they lost their second son, Edwin McVicker, who died and was buried in Shanghai, Kiangsu.

While the Geratys were on furlough in 1947, the Board of Trustees appointed Thomas president of the college, and he assumed the responsibility with his family at the permanent campus site, at Chiao Tou Tseng. The communist army meanwhile was gaining sweeping control of mainland China, and it was not long before both the Division officers and the American Embassy recommended evacuation once more. A ship was charted. College personnel, equipment, and supplies sailed up the Pearl River and down to Kowloon, returning to Hong Kong, the college merging at Clearwater Bay with the South China Training Institute, where previously it had had a similar experience.

In 1951 the General Conference called Geraty to the presidency of Middle East College at Beirut, Lebanon, in the newly established Middle East Division. For the first four years there he concurrently was Division Education Secretary and convened a Division-wide Education Council to establish educational policies. While on furlough during the eleven years with the Middle East Division, Thomas earned his doctorate in education from the University of Southern California.

In 1959 the General Conference of Seventh-day Adventists appointed Geraty to serve as Associate Secretary of the General Conference Education Department, during which time he edited The Journal of Adventist Educationfor seven years and counseled and supervised SDA education in nine of the world divisions of the church. His main contributions, undoubtedly, were to promote basic SDA education philosophy for implementation, to emphasize excellence in the quality of administration and instruction, to provide separate boards of control for secondary schools and colleges, and to initiate joint teams of visiting committees for regional and professional accreditation.

In proposing to start doctoral programs in education at Andrews University, the Board of Trustees called Thomas in 1970 from the General Conference where he had served for eleven years. He was both the Education Department Chairman and its first director of the doctoral programs. Hazel, during those years, not only entertained and kept house, but she also taught in the Andrew University elementary school. They both retired in 1977 from denominational employ.

The Geratys have had four children: Lawrence Thomas, Ph. D.; Edwin McVicker  ( deceased ); Ronald Douglas, M.D.; and Kathleen Marie.

Only a few months after their retirement there was an emergency call from the Hawaiian Mission Academy for help when the principal was hurt in an accident, and the Geratys went to Honolulu for one semester. Later Thomas served for three years as the Education Superintendent of the Hawaii Conference. Since that time they have helped with teaching, counseling, and conducting seminars in SDA colleges and universities in both North America and in the Far Eastern Division of Seventh-day Adventists.