Justice Johnson was born in Calvert County, Maryland, on November 4, 1742, in the state where he was raised, spent almost all of his early professional life and from which he would be appointed to the SCUS. He did not receive any formal university education, which was not at all uncommon at the time.
Justice Johnson entered private practice for two years in Annapolis, Maryland, starting in 1760, and then served as a member of the Lower House of the Maryland Proprietary Assembly from 1762 to 1774. He became a Delegate to the Continental Congress the same year he left that office, serving until 1777, when he began a three-year term as the first Governor of Maryland; concurrent with his time in the Continental Congress, he was also briefly a Brigadier General fighting on the Continental Army’s side in the American Revolutionary War, 1776-1777. After Justice Johnson left the governor’s office in 1780, he embarked on another stint in private practice, and worked as a private attorney in Frederick, Maryland for a decade. During this time, he also served in the Maryland House of Delegates for two two-year terms, from 1780 to 1782 and then from 1786 to 1788. Justice Johnson left private practice in 1790 to become Chief Judge of the Maryland General Court, where he remained until his elevation to the SCUS.
Justice Johnson received a recess appointment from President George Washington on August 5, 1791, to a seat vacated by Justice John Rutledge, and was nominated to the same position by President Washington on October 31. He was confirmed by the United States Senate on November 7, and received his commission that day. Justice Johnson served his entire tenure (which stands as the shortest in SCUS history to date) on the Jay Court, and his service was terminated on January 16, 1793, due to his resignation.
Justice Johnson is not particularly well remembered today. This is most likely at least partially a result of his extremely short tenure, which ended early in large part because of the rigors that Justices in that era had to endure when riding circuit.