Edward Cain was born around 1840 in the Fort Mott area of Orangeburg County. Born a slave, Cain was owned by Captain A.J. Frederick. He was able to read and write and served as a carpenter and wheelwright. During the Civil War, he escaped to serve in the Union Army. After the war, he became a delegate for Orangeburg County at the Constitutional Convention in 1868. That same year, he was elected to the South Carolina State House of Representatives until 1870.
In November 1872, Cain was elected to his first term as Sheriff of Orangeburg County. In 1874, Sheriff Cain was sent to Columbia to arrest Governor Franklin J. Moses who was indicted for misappropriation of state funds.
Cain and his wife, Minty, had one son, James L.
Sheriff Cain died on January 13, 1892 in Charleston. He was 52. He is buried in the Fort Motte area of Calhoun County.