Buried at Gloria Dei (Old Swedes’)
In 1908, Johnson was one of the co-founders of the Swedish Colonial Society, whose members traced their ancestry to the pre Revolutionary War Swedish colonists. Johnson served as instructor and later assistant professor of Scandinavian Languages at the University of Pennsylvania from 1910 to 1921. After serving as President of the Historical Section of the American Division of the Gothenburg Exhibition in Gothenburg, Sweden, in 1921 Johnson accepted the post of Director of the African Educational Expedition to Angola, during 1922-1924. In the years after the expedition, Johnson published a Kimbundu English Portuguese dictionary and a narrative about his travels.
Starting in 1926, Johnson was corresponding secretary of the Swedish American Tercentenary Association which conducted an endowment campaign to celebrate the 300th anniversary of Swedish settlement in North America and to endow the American Swedish Historical Museum. In 1938, Prince Bertil of Sweden dedicated the American Swedish Historical Museum in a celebration which also included the dedication of Fort Christina Park in Wilmington, Delaware.
Johnson was museum director and curator from 1928 until 1943. Johnson conducted extensive research both in the United States and in Europe into the Swedish American Colonial period. He wrote numerous books and spoke extensively regarding the subject. He continued to take an active interest in the activities of the American Swedish Historical Museum and the Swedish Colonial Society throughout his life. In 1961, Amandus Johnson was selected by the two Swedish District lodges of the Vasa Order of America to be Swedish-American of the Year. He is most associated with his epic two volume history The Swedish Settlements on the Delaware 1638- 1664, which was also published in Swedish as Den första svenska kolonien i Amerika (1923).