The Irishman Alexander Porter emigrated in 1801, together with an uncle who then settled in Nashville (Tennessee), in the United States. After he had experienced only a limited education, he first visited the Clemenceau College, before he studied law, was admitted in 1807 to the bar and began to practice in the then still the Orleans Territory belonging Attakapas region. In 1812 he was a delegate attended the meeting at which the first constitution of the new state of Louisiana was created. After the founding of the state from 1816 to 1818 he sat in the House of Representatives from Louisiana.
Between 1821 and 1833 before he as a successor of in a shipwreck who were killed Josiah S. Johnston in the U.S. Senate in Washington DC Porter belonged to the Supreme Court of Louisiana as a judge, was chosen. Porter, a member of the Whigs, took his seat on December 19, 1833 and kept it until January 5, 1837, when he resigned for health reasons. As a result, he again worked as a lawyer in Attakapas and also worked as a planter. He was again elected to the U.S. Senate, where he would therefore belongs from March 4, 1843 However, he resigned his mandate again because of health problems not to, which then fell to Henry Johnson. Porter died the following year in Attakapas and was buried in Franklin.