As a teenager, he became a bond salesman for the predecessor company to the Harris Trust Bank. In 1903, he opened a Chicago branch office for the recently founded New York investment firm, N. W. Halsey Company. Stuart competed with New York bankers when he started handling small bond offerings for the utility magnate
Samuel Insull in 1907. When N. W. Halsey died around the year 1911, Stuart bought the Chicago office of that organization and established Halsey, Stuart & Co. In 1922, due to his growing trust in Stuart, Insull entrusted Stuart with a
$27 million bond offering at a time when the bond market did not look promising. Stuart was able to move the issue at an extremely low interest rate and as a result, Stuart become one of Insull's chief financial officers. Later in his life, Stuart recalled that he and Insull did about $2.3 billion worth of business. == Death ==