Born in Portland, Oregon, on June 14, 1931, G. Thomas Edwards grew up in Taft, Oregon and was raised by his mother and stepfather, Marie and Nahum “Mac” McMullen. He earned his bachelor's degree from Willamette University in 1953, and his master's and doctorate from the University of Oregon in 1963. He also served in the United States Army from 1954 to 1956. In 1957, he married Nannette W. McAndie, and they had two children, Stephanie and Randall. While in graduate school, he taught public school in Eugene, Oregon, before accepting a position at San Jose State College. In 1964, Edwards accepted a position in the Whitman College history department, where he primarily taught classes on American history, particularly in Western American history, the Civil War, and Reconstruction.

Edwards held numerous leadership positions on the faculty, including elected chair of the faculty. He was named the William Kirkman Professor of History in 1985, and earned both the Burlington Northern Teaching Achievement Award and the Robert Y. Fluno Teaching Award during his career. Upon his retirement in 1998, his former students joined together to fund the G. Thomas Edwards Award for Excellence in the Integration of Teaching and Scholarship. In 1982, Edwards agreed to write a scholarly history of Whitman College, which was published in two volumes: The Triumph of Tradition: The Emergence of Whitman College, 1859-1924, and Tradition in a Turbulent Age: Whitman College, 1925-1975. Edwards was a regular presenter at reunions and alumni events across the country, and he led many trips for the Whitman College Alumni Association. He gave presentations on the emergence of Whitman College, Marcus and Narcissa Whitman, and student activism in the 1960s. The Alumni Association presented him with its award for faculty service in 1996.

Edwards continued his research and writing throughout his retirement. In 2003, he received the Robert Gray Medal from the Washington State Historical Society for lifetime achievement in teaching regional history. During his career, he published four books and dozens of articles in scholarly journals. Edwards died on January 10, 2018 in Portland, Oregon. In his eulogy for Edwards, former Whitman College President Robert Allen Skotheim wrote, “Tom was the complete liberal arts professor, as he aspired to be: teacher, scholar, advisor, campus citizen. He was also our good friend.”