Oliver Traphagen was born in Tarrytown, New York on September 3, 1854. He moved with his family to St. Paul in the 1870s and became an apprentice in the office of architect George Wirth. Traphagen relocated to Duluth in 1882 and worked as a carpenter and architect during the 1880s. In 1890, he became a partner of Francis Fitzpatrick and the two men practiced together until Fitzpatrick moved to Washington, D.C. in 1896. Traphagen continued to practice in Duluth for two more years and then moved to Honolulu, Hawaii. He maintained a successful practice there until 1907, and then moved to Alameda, California. Traphagen retired about 1925 and died in Alameda on October 21, 1932.

Francis Fitzpatrick was born in Montreal on April 9, 1863. His earliest known work experience was with L.S. Buffington in Minneapolis, where he was employed as a draftsman from 1884 to 1887. He then became a draftsman for Fremont and George Orff in 1888-1889 and, for a brief time, was manager of the Minnesota Decorating Company. In 1889, Fitzpatrick moved to Duluth and entered partnership with Oliver Traphagen, where he stayed until 1896 at which time he relocated to Washington, D.C. There he was employed as foreman of the Office of the Supervising Architect of the Treasury (1897-1903). During that time, he is known to have supervised construction of the Chicago Post Office and possibly the U.S. Government Building in Chicago as well as working as a freelance draftsman. In 1903, he set up his own practice and in 1918 became head of the architectural department of the Bankers Realty Investment Company, Omaha, NE. About a year later, Fitzpatrick was residing in Evanston, IL, and was described by a contemporary as a "hearty, red-faced, stoutish man who seemed older than the 56 years" he was by then. He died in Evanston on July 11, 1931.