[1] Simonton received a recess appointment from President Grover Cleveland on September 3, 1886, to a seat on the United States District Court for the District of South Carolina vacated by Judge George Seabrook Bryan.

He was confirmed by the United States Senate on January 13, 1887, and received his commission the same day.

His service terminated on December 28, 1893, due to his elevation to the Fourth Circuit.

[1] Simonton was nominated by President Cleveland on December 11, 1893, to a joint seat on the United States Court of Appeals for the Fourth Circuit and the United States Circuit Courts for the Fourth Circuit vacated by Judge Hugh Lennox Bond.

His service terminated on April 25, 1904, due to his death in Philadelphia, Pennsylvania.