Thomas Coltrin Keefer was born on November 4, 1821, in Thorold, Niagara Regional Municipality, Ontario.

He was a civil engineer, businessman, and author. He was born into engineering, his father George Keefer (1773-1858) being the chairman of the Welland Canal Company. In 1838, after attending Upper Canada College, Toronto, he began his engineering training by working on the Erie Canal, N.Y., and continued his learning experience on the Welland Canal, Ontario (1840-1845). He surveyed a railway connecting Kingston, Ontario, and Toronto (1851), was in charge of the survey for a line between Montreal and Kingston, and determined the site for the Victoria Bridge that crosses the St. Lawrence River into Montreal. One of his best-known achievements was the construction of the Hamilton Waterworks (1859). He became chief engineer of the Montreal Water Board and also built the Ottawa Water Works (1874). Keefer was a co-founder and the first president of the Canadian Society of Civil Engineers (1887). He was also president of the American Society of Civil Engineers (1888) and of the Canadian Institute. He was made a Fellow of the Royal Society of Canada in 1890 and was its president from 1898 to 1899. He was the author of the paper "The Philosophy of Railroads and Other Essays" (1849). The Keefer Medal was established in 1942 and is awarded annually by the Canadian Society for Civil Engineering for the best civil engineering paper in hydro-technical, transportation, or environmental engineering.

In 1848, he married Elizabeth McKay (1830–1870) and in 1873, he married Annie MacKinnon, née McKay (1825–1906). He died on January 7, 1915, in Ottawa, Ontario.