In July 1769, Archer commenced the practice of law in Harford County.[3] He was a member of the Revolutionary committee from 1774 to 1776, and later raised a military company during the American Revolutionary War.[1][3] He was a member of the first state constitutional convention of 1776,[3] and served in the Maryland House of Delegates from 1777 to 1779.[1] During the Revolutionary War, Archer was volunteer aide-de-camp to General Anthony Wayne at Stony Point. On June 1, 1779, Archer was made a captain and subsequently a major in the Continental Army.[1]
Archer was elected as a Democratic-Republican to the Seventh, Eighth, and Ninth Congresses, serving from March 4, 1801, until March 3, 1807. He founded, with his son Thomas Archer, the medical and chirurgical faculty of Maryland in 1799.[1] In 1810, Archer documented a case of superfecundation, more specifically called "heteropaternal superfecundation," in which a Caucasian woman gave birth to mixed twins — one Caucasian, one Afro-Caucasian - after having had intercourse with two men of differing race within a few weeks.[citation needed]
Personal life
Archer married Catherine Harris on October 18, 1766. His son was Stevenson Archer, chief justice.[3]
Archer died at his country home, Medical Hall, near Churchville, Maryland, on September 28, 1810, and is interred in the Churchville Presbyterian Church cemetery.[1][3]
A descendant of Dr. John Archer, one Henry Wilson Archer and his wife Mary Elizabeth Walker Archer, bought the 65 acre farm "Shamrock" from Ellen Howe Davis in 1850. The farm was retained in the Archer family until 1955 when it was sold to the Sparr Construction Company to become the current development of Shamrock in Bel Air. The mansion on the property, along with 5 acres was purchased by Nicholas J. Bonge, and named the "Christian Bible Center". He had plans of restoring the home for a Christian orphanage. After his untimely death in 1961, it was resold and, sadly, burned to the ground by a contingent of 70 Harford County Firemen in October 1963 to make way for the development.<Historical Society of Harford County>[citation needed]
John Archer School, a special education school built in 1971 in Bel Air was named after Archer. In June 2022, the school board voted to rename the school to Harford Academy on Campus Hill due to Archer's ownership of slaves.[5]