In 1856, he moved to Minneapolis, Minnesota, and engaged in manufacturing and mercantile pursuits, largely in the manufacture of lumber and flour. He became a member of the board of directors of the First National Bank upon its establishment in 1864.
Fletcher was elected a member of the Minnesota House of Representatives 1872 – 1886, and served as speaker from 1880 to 1885. Beginning with the 1892 election, he was elected as a Republican to the 53rd, 54th, 55th, 56th, and 57th congresses (March 4, 1893 – March 3, 1903). Fletcher served as chairman of the Committee on Expenditures on Public Buildings (57th congress. He was defeated in the 1902 election to the 58th congress, but was elected to the 59th congress, (March 4, 1905 – March 3, 1907). He declined to be a candidate for reelection and retired from active business.