Joseph Thomas Martz (7 May 1918-1 September 1979) was the only son of Joseph Manning Martz (11 September 1889-5 August 1934) and Ethel Beans (28 October 1891-9 July 1965). Born and raised in Loudoun County, he attended Round Hill School and Strayer College of Accountancy. After his father died, Martz went to live with his uncle, James Bernard Martz (23 July 1895-27 August 1950), in Washington DC, where he pursued a career in insurance.

Pending the start of World War II, Martz joined the army on 2 December 1941, and when war was declared, he shipped out to Eastern Europe and Northern Africa, where he served without incident. He was separated from the army on 31 December 1945.

After the war, Martz became chief bookkeeper at Loudoun County Livestock Market, and then the deputy treasurer for Loudoun County. In 1951, he ran for the office of Clerk of Loudoun Circuit Court against the previous circuit court clerk, Edward O. Russell (27 October 1875-15 February 1953), who had held the position for 23 years. Martz won with 65% of the vote. As clerk of the circuit court, Martz kept records of all court cases and land deeds, issued licenses, collected fines, and managed juries. He also became president of the Virginia Court Clerks Association. In 1965, he was elected director of First National Bank of Purcellville.

On 31 October 1951, Martz married Clara Frances Miller (20 May 1918-3 October 2001), a Purcellville native and secretary at William P. Lipscomb Company in Washington DC. They lived in Purcellville and had three daughters: Anne Katherine Martz (27 August 1953-5 October 2010), Gayle Manning Martz Kohlbry (b. 22 December 1955), and Joyce Thomas Martz Grier (b. 5 December 1956).