In September 1789, President George Washington nominated Johnson to be the first federal judge for the District of Maryland, but he declined the appointment. In 1790 and 1791, Johnson was the senior justice in the Maryland General Court system. In January 1791, President Washington appointed Johnson, with David Stuart and Daniel Carroll, to the commission that would lay out the federal capital in accordance with the Residence Act of 1790. In September 1791 the commissioners named the federal city "The City of Washington" and the federal district "The Territory of Columbia".