Adam Gentles Thomson was born in Duluth on July 22, 1888. He attended Duluth public schools before heading east to boarding school at the Hill School in Pottstown, Pennsylvania. In 1911 he was graduated from the Sheffield Scientific School at Yale University. Newspaper articles indicate he may have attended Macalester College in St. Paul at some point.
His graduation from Yale did not go off without a hitch: He found himself trapped on the top floor of the Tontine Hotel in New Haven, Connecticut, when it was engulfed in flames; he was staying at the hotel while waiting for commencement exercises and escaped unharmed. In 1914 he had an attack of appendicitis while at the family ranch in New Mexico; the Duluth newspapers covered his illness as his father raced to his bedside. A. G. was placed on a train to Kansas City to have the operation which saved his life.
After college A. G. went to work for his father in the grain trade. When his father passed away in 1921, he assumed the presidency of A. D. Thomson & Co., grain traders, and became the chairman of Kelley-How Thomson, hardware wholesalers. A. D. Thomson closed up shop in 1937, but Thomson remained a member of the Board of Trade until 1949, maintaining an office in the Alworth Building. He also oversaw operation of the family’s T.O. Ranch in Raton, New Mexico, a cattle ranch that had grown to over 400,000 acres. A. G. Thomson served as a director of Duluth’s First National Bank and American National Bank and was also a large stockholder in the Great Northern Railroad, the American Steam Barge Company, and a number of mining and railroad ventures; many of these holdings were no doubt passed down to him by his father.
On April 14, 1917, he married Clara McConnell of Helena, Montana, at the St. Regis Hotel in New York City, where they had met three years earlier. Upon their engagement, A. G’s father displayed his famous generosity, giving his future daughter-in-law a pearl necklace worth an estimated $130,000—well over $2 million today. The Duluth News Tribune announced the newlyweds would live at 2005 East Third Street, but they instead moved to 2617 East Third Street, where they stayed until 1925 (this is the house that now operates as a bed and breakfast; it was also once the home of former Duluth mayor John Fedo). The Thomsons then moved to 3500 East Superior Street to a property that once occupied the entire square between Superior Street and Greysolon Road and 35th and 36th Avenues East. The Thomsons had three children, Alexander Douglas (1919), Adam Gentles Jr. (1922), and Odell McConnell (1923), named for Clara’s father.
The Thomsons also maintained homes on the Brule River in northwestern Wisconsin and in Miami Beach, Florida. Clara died July 2, 1937, in Manhattan. Adam G. Thomson died on February 17, 1955, of a heart attack at his winter home in Miami Beach. In Duluth, Thomson belonged to the First Presbyterian Church, the Northland Country Club, the Kitchi Gammi Club, and the Chamber of Commerce. He also belonged to the Yale Club and the Indian Creek Country Club in Miami Beach, Florida.
Kelley-How-Thomson merged with Duluth’s Marshall-Wells Company following A. G.’s death in 1955. By 1958 the conglomerate was liquidated.