Congdon held several offices throughout his life, serving as assistant United States attorney for the district of Minnesota from 1881 until 1886, as a member of the
Minnesota House of Representatives from 1909 until 1913, and as a member of the Duluth charter commission from 1903 until his death. The 1909 Legislature was dominated by the tonnage tax, which would place a tax on all iron ore shipped out of state by companies that did not manufacture steel in Minnesota. Opponents, led by Congdon, argued that such a tax would inhibit the development of lower-grade iron ore properties, something Congdon was heavily invested in. The opposition succeeded in stopping the legislation, but Minnesota would eventually pass a tonnage tax in 1921. Congdon was re-elected for the 1911 Legislature. As a returning legislator, Congdon had more influence and served on eleven committees. He was chair of the Reapportionment (Redistricting) Committee. As the leader in charge of redrawing the state's legislative districts, he attempted to give northeast Minnesota and the Twin Cities more senators. The boundaries were drawn in such a way to ensure more political power to the steel industry and those against the tonnage tax. His measure would eventually fail. Congdon also voted against recall elections, against temperance measures, for limitations on workers going on strike, and for free public transport to policemen and firefighters. Along with his pro-brewery group of politicians, he was aligned with stopping a vote on ending child labor. In a record of the 1911 Legislature, Congdon was described as an intelligent and strong legislator who nevertheless “sacrificed all his fine qualities” to work with "brewery representatives and professional politicians", missing an opportunity to make the "legislature truly representative of the people". In 1916, he was made a member of the Republican National Central Committee, and his opinions carried weight in the councils of the party. He was a member of various professional, historical, scientific, social, and fraternal societies and associations. He had membership with the
Kitchi Gammi Club, Northland Country Club, Commercial Boat Club, and Duluth Boat Club, all in Duluth; the Minnesota Club of St. Paul; the
Minneapolis Club of Minneapolis; the University Club of Chicago; the Duquesne Club of Pittsburgh, Pennsylvania; the Bankers Club of New York; the Commercial Club of
North Yakima; and with various college fraternities, including the Upsilon Kappa,
Psi Upsilon,
Theta Nu Epsilon, and
Phi Beta Kappa. A contemporary biographer has said of him: "Those who really knew Mr. Congdon found in him a man of tender heart and warm, human sympathies. His philanthropy was general and quite well known, although he sought to keep it under cover and shrank from publicity in this regard. He was a close student of government and state policies, a foe of waste and inefficiency, a friend of political progress as he saw it, a champion of clean public life and sound government. He was always the good citizen, eager to have his part in every forward movement in directions that he judged to be wise." ==Family==