Robert Holmes Baker, businessman, prison reformer, and prison administrator, the son of Robert and Annie (Miller) Baker, was born in Memphis, Tennessee, on September 4, 1858. He attended East Tennessee University for two years before moving to Texas, where from 1882 to 1896 he was a merchant at Waco. From 1896 to 1904 he was Texas manager for Equitable Life Assurance Society. He was a business partner of political leader Edward M. House. Baker was president and general manager of the Trinity and Brazos Valley Railway from 1904 to 1911. In 1912 he bought the Texas Central Railroad and served as president of the line until 1914, when he bought the Wichita Falls Railroad to sell both lines to the Missouri, Kansas and Texas system. Later Baker became president of the Houston Terminal Warehouse and Cold Storage Company and chairman of the board of the Seaboard Life Insurance Company. He was captain of the Waco Light Infantry, Texas National Guard, from 1886 to 1889 and from 1902 to 1904 was a colonel on the staff of Governor S. W. T. Lanham.
From 1924 until about 1927 Baker served as chairman of the Texas Committee on Prisons and Prison Labor, an organization committed to penal reform. Governor Dan Moody appointed Baker to the reorganized Texas Prison Board, which he served as chairman from June 16, 1927, through March 25, 1929, when he resigned. While leading the administrative agency for the prison system, Baker worked closely with advisor Elizabeth Speer, whom he and other reformers regarded as an expert in the field of penology. He fired employees who mistreated prisoners, reduced corporal punishments, and supported the publication of an inmates' newspaper, the Echo. Baker also advocated the sale of existing prison properties in East Texas and the Gulf Coast region and their replacement with a modern prison to be constructed near Austin. However, he and Moody failed to persuade the Texas legislature to support the proposal.
Baker, who resided in Austin before the final eight years of his life in Houston, was instrumental in perfecting plans for the enlargement of the campus of the University of Texas. He married Nellie Faulkner on October 19, 1886; they had three children, including philanthropist Burke Baker. Baker was a Democrat and a Baptist. He died in Houston on January 9, 1935, and was buried there.