[5] At the age of seventeen he became a tutor in the family of General Thomas Posey,[7] of The Wilderness, twelve miles west of Fredericksburg, but after a few months resumed his studies with his former teacher.

On October 1, 1791, he was licensed to preach, ordained by the presbytery of Hanover on June 9, 1794, and for seven years was an itinerant pastor in Charlotte and Prince Edward counties.

He was appointed the president of Hampden–Sydney College,[8] where he served from 1797 until a revolt among the students forced him to retire in 1806, and from 1807 to 1812 he was acted as pastor of the Old Pine street Presbyterian Church of Philadelphia.

The Presbyterian Historical Society in Philadelphia, Pennsylvania has a collection of Archibald Alexander's personal papers dating from 1819 to 1851 including outgoing correspondence, manuscript articles and lecture notes.

[5] His grandson, William C. Alexander (1848–1937), was an executive with the Equitable Life Assurance Society, author, and founder of Pi Kappa Alpha fraternity.