The academy was established by charter of the Illinois General Assembly in 1839 to provide students with a classical education.

The academy's original building, Old Main, was constructed in 1855-6, and is on the United States' National Register of Historic Places.

In 1856 the first building, Old Main, was completed at a cost of $19,000 and opened for classes, but the first diploma was not awarded until 1872 when Laura Davidson, the granddaughter of James Gifford, Elgin's founder, earned the honor.

All together, 153 Civil War veterans, whose names are inscribed on the base of two authentic Union cannons, were associated with the academy.

In 1874, 274 students were enrolled and high school degrees were offered in the areas of College Preparatory, Normal, English, Classical, Latin-Scientific, and Business.

[5][6][7][8] The school occupied a 18-acre (73,000 m2) campus 35 miles (56 km) northwest of Chicago in the Historic District of the city of Elgin.

Elgin Academy's sports teams were nicknamed the Hilltoppers (the school being built on a hill), and their mascot was Foxman, after the nearby Fox River.