Thornton Leigh Page, son of Leigh and Mary Thornton Page, was born in New Haven, Connecticut on August 13, 1913. The younger Page attended school in New Haven (where his father served on the faculty of Yale University) before earning a bachelor's degree in physics from Yale in 1934, and being named a Rhodes Scholar. Page studied astrophysics at Oxford and completed a thesis on the spectra of planetary nebulae. He was elected to fellowship by the Royal Astronomical Society and was awarded a Ph.D. in 1938. That same year, Page married Helen Ashbee in Kent, England; the couple soon moved to Chicago, where Page had been hired as an instructor in astronomy. The Pages would have one child before divorcing in 1945.

Just prior to World War II, Page joined the Naval Ordnance Lab in Washington, DC, working on magnetic mines and countermeasures. He was later transferred to London and Hawaii, where he was working during the attack on Pearl Harbor. Page was enrolled as a lieutenant (junior grade) in the U. S. Naval Reserves and assigned to Pearl Harbor, serving in the minelaying operations-research group. Following the war, he was assigned to mine removal in the Inland Sea.

Page returned to the University of Chicago in 1946 and married Lou Williams, a geologist, in 1948. The couple would have two children. Page worked in the McDonald Obervatory, obtaining spectra of double galaxies. The results of his work contributed to early theories of dark matter. Page was promoted to assistant professor in 1947, but left the University of Chicago to accept appointment as deputy director of the U. S. Army's Operations Research Office. In 1958, he became head of Wesleyan University's astronomy department.

A 1961 automobile accident left Page blinded in one eye and led to a five-month hospital recovery. The Pages took extended leave and moved to California, where they co-edited the eight-volume Sky and Telescope Library of Astronomy. Page worked on a number of projects in the following years: working on the space-tracking program at Harvard-Smithsonian Observatory, upgrading the reflector of Argentina's Cordoba Observatory, and lecturing to astronauts on astronomy at NASA's Manned Spacecraft Center. He served as co-investigator of Apollo XVI's S201 experiment on far-ultraviolet observations.

Page resigned from Wesleyan in 1971, remaining in Houston to work in the Naval Research Laboratory. He retired in 1976 but continued to work, completing various public information works for NASA, teaching astronomy at the University of Houston-Clear Lake, and organizing a long-running Brown Bag Seminar at Johnston Space Center. Thornton L. Page died in Houston, Texas on January 2, 1996.