He was educated at the University of Chicago Laboratory Schools. After high school, he was educated at Princeton University, graduating in 1900.
In 1901, they renamed the company the Quaker Oats Company, to take advantage of the brand previously built up by Crowell"s Quaker Mill Company. In 1907, at age 30, Stuart was named a director of the Quaker Oats Company and soon became thoroughly acquainted with the business. Stuart took over as Chief Executive Officer of the Quaker Oats Company in 1922, at age 43.
During Stuart"s time as Chief Executive Officer, the company introduced new products, such as Puffed Wheat and Puffed Rice.
The company purchased Aunt Jemima in 1925. The company diversified in 1942 with the purchase of dog food brand Ken-L Ration, to be followed up by the acquisition of the Puss "n Boots cat food brand in 1950.
Stuart stepped down as Chief Executive Officer in 1953, handing the reins to his designated successor Donold Lourie. In addition to his work at the Quaker Oats Company, Stuart sat on the board of directors of International Harvester, the Canadian Imperial Bank of Commerce, the Pennsylvania Railroad, and Northern Trust.
He was a trustee of Princeton University and of the University of Chicago.
Stuart was married to the former Ellen Shumway. Stuart died at Lake Forest Hospital on December 26, 1969.
Also, in 1947, at the request of President of the United States Harry Truman, Stuart was a member of the Hoover Commission.