He graduated from the Carolina Military Institute, studied law in the University of Virginia at Charlottesville, was admitted to the bar in 1883 and practiced in Bennettsville.

At a time when Benjamin Tillman was making demagogic appeals to the white working class, McLaurin became one of the first upper-class South Carolinians to support him.

Tillman in 1892 pinned the nickname "Little Curly Headed Joe" that stuck for the remainder of McLaurin's life.

Tillman accused him of accepting bribes from the Textile industry, which led to the famous fistfight between the two on the Senate floor on 22 February 1902.

He was appointed and subsequently elected as a Democrat to the U.S. Senate to fill the vacancy caused by the death of Joseph H. Earle and served from June 1, 1897, to March 4, 1903; he was not a candidate for reelection.