In a special election on February 14, 1888, to fill the vacancy caused by the death of Seth C. Moffatt, Seymour was elected as a Republican from Michigan's 11th congressional district to the 50th Congress, serving from February 14, 1888, to March 3, 1889.
On February 14, 1888, Seymour was selected as a Republican for Michigan's 11th congressional district in the 50th Congress to replace Seth C. Moffatt and served from February 14, 1888, until March 3, 1889.