It was founded in 1826 under prominent but controversial theologian and professor Samuel Simon Schmucker (1799-1873) for the recently organized General Synod of the Evangelical Lutheran Church in the United States.

Gettysburg continued to add to its trail breaking in the American scene by granting tenure to a female professor, Bertha Paulssen, in 1945, and graduating, in 1965, the first woman to be ordained by an American Lutheran church body, Elizabeth Platz (graduated in 1965 and ordained in 1970).

Samuel Simon Schmucker, ordained in 1820, actively lobbied for the establishment of a seminary and began theological training for students at his parsonage in New Market, Virginia.

[5] The board of directors first met on March 2, 1826, in Hagerstown, Maryland, with the first order of business being to select a site for the seminary.

They rejected proposals from Carlisle, Pennsylvania (at Dickinson College) and Hagerstown[6] and the "Gettysburg Theological Seminary"[7] was established on August 1, 1826.

The I Corps streamed across Seminary Hill and through the town of Gettysburg, covered by a delaying action on the grounds by the famed Iron Brigade.

The seminary building had begun to be used as a field hospital for soldiers of both armies during the first day, and this continued throughout the engagement and after the battle was over.

[24] In 1895, during the battlefield commemorative era, the Gettysburg Park Commission telfordized the seminary's north–south avenue[25] (resurfaced in 1927).

[29] In about 1960, the seminary purchased the nearby Elsie Singmaster Lewars home[24] and in 1961, the Adams County Historical Society moved from the courthouse basement[30] to Old Dorm (added to the NRHP in 1974).