Sydenham Moore went to classical subjects. He attended 1833-1836, the University of Alabama in Tuscaloosa. Moore studied law, was admitted to the bar and began to practice in Greensboro. He was 1840-1846 and 1848-1850 Judge at the Court of Greene County. Then he was in 1857 a judge of the District Court. During the Mexican-American War, he served from June 1846 and June 1847 as Captain in Colonel Coffey's Regiment of Alabama Infantry. Furthermore, he was promoted to brigadier general in the Alabama Militia.
Moore was elected to the 35th U.S. Congress, where he served from March 4, 1857 until his resignation on 21 January 1861. During the American Civil War, he served as a colonel in the 11th Alabama Regiment of the Confederate Army. Moore died in 1862 at the wounds, which he won at the Battle of Seven Pines. He was buried at the city cemetery of Greensboro (Alabama ).