The site for Thornton Township High School was decided by a special election on May 28, 1898, where Harvey was selected over Dolton by a 1,504 to 1,123 vote; with the estimate of the school's cost being $40,000.[6] Oscar L. Murray was the architect of the building that by October 1898 was now costing $35,000, and had plans that included physical and biological laboratories, a library, gymnasium, a 280 seat assembly room, bicycle, and lunch rooms.[7]
By May, 1899, the plans had firmed up to include a two story structure with basement, with an interior to be finished in red oak. Heat would be provided by steam, with electric fans and an automated clock and signal system. The main floor assembly room was expanded to seat 700. Construction was set to begin in June, with completion in October.[8] The original building, located at 154th Street and Columbia Avenue.[9]
In 1913, Thornton was one of nine schools (and the only south suburban school) invited to found what would become the Suburban League, which mostly consisted of schools like Thornton which had formerly been members of the Cook County High School League.[10]
1928 saw 16 year old Betty Robinson (between her junior and senior years at the school) not only win the very first Olympic gold medal awarded to a woman in the 100 meters (at the 1928 Summer Olympics in Amsterdam), but set a world record which would stand for four years.[11]
With the advent of World War II, like many high schools, Thornton made changes to accommodate the war effort. Evening classes for adults started in 1942 to begin training people for necessary war jobs.[12] By 1943, the school was open 87 hours each week, and had been converted over almost exclusively to wartime training.[13]
Additions were made to the building in 1912 ($140,000), 1927 ($345,000), and 1937 ($300,000).[14][15] A third floor was added in 1948.[16] 1949 saw the addition of a new physical education facility, including a natatorium, wrestling rooms, locker facilities, and class rooms for health classes, in addition to two gyms, one of which could seat 3,500 for basketball games.[17][18] The new gymnasium was ultimately dedicated in April, 1950.[19]
