Alexander Taggart McGill was born in Canonsburg, PA in 1807. While primarily known for his work as General Assembly statesman and professor of theology, McGill held a variety of professions? lawyer, land surveyor, Indian liaison and missionary? during a lifetime which spanned the greater part of the 19th century.

In 1826, McGill received a degree from Jefferson College (Washington, PA). Aside from a brief sojourn in Georgia and Alabama, McGill spent a good part of the next two decades working as a missionary and minister throughout Carlisle County, PA and the Delaware Valley area. In 1848, McGill was appointed Moderator of the General Assembly (Old School) and held the distinction of being the youngest man of his time to hold that position. After fulfilling his duties as Moderator, McGill remained active in the General Assembly and served on various committees until the early 1870s.

As a theologian, McGill held conservative views on religion and on the moral responsibility of the Presbyterian Church to its congregation. Apparently alarmed by the growth of such popular religious movements as Transcendentalism, McGill often expressed fears that the American political climate invited moral decline. During the later years of his life, McGill advocated a greater joining of Church and State. Unlike many of his conservative colleagues, McGill was a vocal opponent of American slavery and wrote numerous articles on the subject. Although McGill originally supported the African Colonization Movement, he seemed to have tempered his view of Liberia as the "promised land" for Afro-Americans by the 1870s. At that time he stated that if blacks chose to remain in America, "we shall stand at their side and rejoice".

While serving as Moderator of the General Assembly, McGill taught church history and government at Western Theological Seminary (Allegheny, PA). In 1852, after having taught for a short time in South Carolina, McGill was elected to a chair at Princeton Theological Seminary. Retiring with the rank of Professor Emeritus in 1883, McGill died in Princeton at the age of 81.

At the time of his death, McGill was survived by six of his eight children, including: Alexander T. McGill, Jr.--a member of the New Jersey State Legislature--and John McGill--Surgeon General of New Jersey. A third son, George, worked as Assistant Surgeon to the U.S. Army during the Civil War.