T.G. Hamilton was born in 1873, in Agincourt (now part of Toronto), the son of James Hamilton and Isabella Glendenning. When T.G. was ten, the Hamiltons and their six children moved to Saskatchewan to homestead near Saskatoon. Not long after two tragedies occurred in rapid succession: T.G.’s father died in 1885 and a year later T.G.'s sister Margaret died of typhoid fever. This and the availability of educational opportunities elsewhere led the family to abandon Saskatchewan in 1891 to move to Winnipeg. T.G. was educated at Manitoba College and the Manitoba Medical College, graduating as an M.D. from the latter in 1903. He lectured in medical jurisprudence and clinical surgery at the Manitoba Medical College, and was an assistant surgeon at the Winnipeg General Hospital. He married Lillian May Forrester three years later and in 1910 set up a private medical practice in a home, later known as Hamilton House, located on what is now Henderson Highway in Elmwood, a suburb of Winnipeg. He and Lillian had four children: Margaret, Glen and in 1915, twins, Arthur Lamont and James Drummond. In terms of religion, the Hamiltons were Presbyterian and later members of the United Church of Canada.