Ralph Haywood Cameron, architect, was born in San Antonio, Texas, on November 10, 1892, the son of Antoine Haywood and Nila (Crawford) Cameron. He attended public school and subsequently worked as an architectural draftsman for architect Alfred Giles and the firm of Adams and Adams. In 1912 he went to Kingsville to supervise construction of the new main house on the King Ranch, designed by Adams and Adams for Robert J. Kleberg. While working for the firm, Cameron also designed the Dewitt County Courthouse in Cuero and remodeled the Gonzales County Courthouse.
In August 1914 he opened his own architectural office in the Majestic Building in San Antonio, and between then and the American entry into World War I he designed numerous houses and small buildings in San Antonio and South Texas. He entered the United States Army in 1917 and attended the first officers' training camp at Camp Funston (now Camp Bullis) and the Army Engineering School at Fort Leavenworth, Kansas. He served as a first lieutenant with the 315th Engineers, Ninetieth Division of the American Expeditionary Force, and saw combat at St. Michel in France. He was gassed on the last day of the war and hospitalized for a time in Paris. While there, he used the opportunity to study architecture briefly at the École des Beaux-Arts.
After the war Cameron returned to San Antonio and in August 1919 reopened his architectural practice. During the 1920s and 1930s he emerged as one of the leading Beaux-Arts-influenced architects in South Texas, along with Atlee B. and Robert M. Ayers and his former employer Carleton W. Adams. Among his best-known works from this period are the Neo-Gothic Medical Arts Building (1925–26), Grace Lutheran Church (1928), the Neo-Spanish Colonial Academic Building at Randolph Field (1929), the Art Deco-influenced Frost Brothers Store Building (1930), and the C. S. Lips residence in Terrell Hills (1940). The Hornaday residence in Monte Vista (1929) is an outstanding San Antonio example of Colonial Revival architecture. Cameron also served as supervising architect for the Scottish Rite Cathedral designed by the Herbert M. Greene Company (1923–24), South Side High School (1930), and the United States Post Office and Courthouse (1937), for which Paul P. Cret of Philadelphia served as consulting architect. In addition to his work in San Antonio, Cameron designed numerous buildings in the Rio Grande valley, among them McAllen High School (1928), the Hidalgo County State Bank in Mercedes (1928), and the A. Y. Baker residence in Edinburg (1930).
From 1929 to 1941 he served in the Texas National Guard, and in October 1941 he was called to active service with the rank of colonel and transferred to the Army Corps of Engineers. He spent forty months in Europe as commander of the 344th Engineer Regiment, which saw action in North Africa, Italy, France, Germany, and Austria. Cameron is credited with building the first bridge over the Rhine near the war's end. After the war he served in the army reserve corps until his retirement in 1952.
He married Mary Fly, the niece of William S. Fly, on July 22, 1923. The couple had four children. Cameron was a founding member of the Texas Society of Architects and a member of the American Institute of Architects. He served for ten years as the director of the West Texas Chapter of the AIA and in 1932 was responsible for bringing the national convention to San Antonio. Cameron was a Methodist and a member of many fraternal and business organizations, including the Scottish Rite, the Elks, the San Antonio Chamber of Commerce, the Argyle Club, and the Menger Patio Club. He died in San Antonio on May 5, 1970.