Duncan Edward Stewart was born in Waba on May 10, 1910, the only son of Duncan G. Stewart and Ethel nee Stewart. He was educated at Renfrew Collegiate and Queen’s University, where he graduated with a degree in electrical engineering in 1934. When his uncle Alexander, who was unmarried, died in 1934, Duncan was asked to enter the business as a partner with his father and his aunt Margaret (who remained a silent partner). In 1936, he married Elizabeth [Bessie] Wallace nee McLaren of Renfrew. They had five children. After his father's death in 1954, Duncan managed the firm alone. In his retirement, Duncan Stewart served for many years as trustee for the Renfrew County School Board. He died in Waba, of lung cancer, on July 31, 1996.