Elected as a Republican to the Fifty-ninth and to the two succeeding Congresses, Bennet served as U. S. Representative for the seventeenth district of New York from March 4, 1905, to March 3, 1911. An unsuccessful candidate for reelection to the Sixty-second Congress in 1910, he was elected to the Sixty-fourth Congress to fill the vacancy caused by the death of United States Representative Joseph A. Goulden of the twenty-seventh district of New York and served from November 2, 1915 to March 3, 1917. He was an unsuccessful candidate for reelection to the Sixty-fifth Congress in 1916.