US Senator. He was born one of five children to Colonel James Henderson Irby (He represented Laurens County, South Carolina, in the South Carolina State Senate and was a Lieutenant Governor of South Carolina) and Henrietta Thompson Earle Irby (Her family the Earle's were also a distinguished South Carolina family), in Laurens, South Carolina. He was educated locally in common public schools and later attended and was educated at the Laurinsville Male Academy in Laurens, South Carolina, Princeton College (later Princeton University) in Princeton, New Jersey, from 1870 to 1871, and at the University of Virginia in Charlottesville, Virginia, from 1871 to 1873. He then studied law and was admitted to the bar in 1875. He then commenced his practice of law in Cheraw, Chesterfield County, South Carolina, before relocating back to Laurens, South Carolina. He married Nancy MacFarlan in 1876, and the couple would have four children together. In 1877, he joined the South Carolina Militia and was appointed to the rank of Lieutenant Colonel. He then served as the Intendant (a public official) of Laurens, South Carolina, in 1877. He was elected as a Member of the South Carolina State Senate and served in that position from 1886 to 1892. He also served as the Speaker of the South Carolina State Senate in 1890. He then decided to run for a seat in the United States Senate and was elected. A Member of the Democratic Party, he then served as a United States Senator from South Carolina from March 4, 1891, to March 3, 1897. While serving in the United States Senate he also served as Chairman of the Committee on Transportation Routes to the Seaboard representing the Fifty-Third Congress. He was not a Candidate for reelection. After his term in the United States Senate expired on March 3, 1897, he was succeeded in office by Speaker of the South Carolina House of Representatives and now United States Senator Joseph Haynsworth Earle (who was also his cousin). He was subsequently an unsuccessful Candidate for election to the United States Senate on the unexpected death of his previous successor and United States Senator Joseph Haynsworth Earle (who was also his cousin), on May 20, 1897. During this time he had also served as a Delegate to the South Carolina State Constitutional Convention in 1895. After leaving politics he resumed his practice of law and also engaged in the agricultural business until his death. He passed away from Bright's Disease on December 9, 1900, at the age of 46, in Laurens, South Carolina, and was buried in the Laurens City Cemetery. His wife who never remarried or had any other children survived him by a number of years and passed away on November 25, 1944, at the age of 89. She was buried beside her husband. His other prominent family members besides his cousin South Carolina State Attorney General and United States Senator Joseph Haynsworth Irby (1847 to 1897), are his great-grandfather United States Representative Elias Earle (1762 to 1823), and other political personalities.