I knew that there were a couple of black Reconstruction Senators from MS, but didn't know their names until I googled "African American Senators." Hiram was born free in NC, and was of mixed race. His free mixed race father married a woman of Scottish heritage. He was a barber, and then went north where he attended college and became a minister. He raised black regiments during the Civil War. After the War he settled in Natchez MS, and it was from there that he began his political career, first as city alderman, then state senator. Next he was elected to the Senate (by the legislature), but not without controversy:
The election of Revels was met with opposition from Southern conservative Democrats who cited the Dred Scott Decision which was considered by many to have been a central cause of the American Civil War. They argued that no black man was a citizen before the 14th Amendment was ratified in 1868. Because election to the Senate required nine years' prior citizenship, opponents of Revels claimed he could not be seated, having been a citizen by law for only two years. Supporters of Revels countered by stating that the Dred Scott decision applied only to those blacks who were of pure African blood. Revels was of mixed black and white ancestry, and therefore exempt, they said, and had been a citizen all his life. This argument prevailed, and on February 25, 1870, Revels, by a vote of 48 to 8, became the first black man to be seated in the United States Senate.
Hiram was the first African-American to serve in Congress, and was considered a good speaker and a man of great intelligence who favored a moderate approach but who insisted on equality. You can read the rest here:
http://en.wikipedia.org/wiki/Hiram_Rhodes_Revels