Mayor Kennett was active in the development of railroads for the area and became president of the Iron Mountain Railway Company in 1853. He was also vice president of the Pacific Railroad Company at its inception, and upon the completion of the first 37 miles of rail, delivered a noted address in opening it to traffic.

Mayor Kennett was born at Falmouth, KY and came to St. Louis in 1825. In time he became a partner with St. Louis merchant Hugh Lawson White. He was first married in 1832 to Miss Martha Ann Boyce, daughter of Colonel Boyce of Farmington, MO. She died in 1835, leaving one daughter. In 1842 he married his cousin, Miss Agnes A. Kennett, and seven sons were born to the family.

Kennett was elected alderman from the fourth ward in 1842 and served three years. He was re-elected in 1846 but soon resigned, because of ill health, to make a tour of Europe. He returned just a short time before the cholera epidemic of 1849. He was a member of Mayor Barry´s Citizens Committee to make recommendations on fighting cholera.

In 1854 he was elected to Congress as a member of the American Party, defeating ex-Senator Thomas Hart Benton. He helped to procure the right of way from the federal government through the grounds of Jefferson Barracks for the Iron Mountain Railroad. In 1856 he was defeated for re-election to Congress and retired to his country home, "Fairview" in St. Louis County. He died in Paris, France on April 12, 1873. Interment was in Bellefontaine Cemetery.