After the war, Dresel signed the peace treaty with Germany, and served as chargé d'affaires for a few months, before retiring from the Foreign Service altogether.

He practiced law with the firm of Goodwin, Dresel and Parker in Boston and lived there on Beacon Street for most of his life.

[5] He was in Europe when World War I broke out in 1915 and he volunteered his services to the U.S. embassy in Berlin, first helping Americans stranded in Germany.

[8] He signed the treaty that concluded hostilities between the United States and Germany and restored their diplomatic relations on November 11, 1921.

The following year, though President Warren G. Harding was prepared to name him ambassador to Germany, he left government service and returned to the United States.

[15] Dresel's papers are preserved in the Houghton Library, including correspondence with William Richards Castle, Joseph Clark Grew, Hugh S. Gibson, Henry Cabot Lodge, and Allen Welsh Dulles.