Manuel C. (M. C.) Gonzales, Mexican-American civil-rights activist, was born on October 22, 1900, in Hidalgo County, Texas, to Ruperto and María Luisa (Carbajal) Gonzales. His grandfather was Gen. José M. J. Carbajal. Gonzales married Cornelia Blank, with whom he had one daughter. On June 6, 1959, he married Rose Olga Solís; they had four children. When his family moved to San Antonio in 1910, Gonzales worked for Francisco A. Chapa at his drugstore and attended both parochial and public schools, then Nixon Clay college in Austin. He subsequently worked as a law clerk for the district judge of Hidalgo County, as chief clerk at the Capitol in Austin, and as a secretary for the Patterson and Love law firm, also in Austin. Although underage, Gonzales served as secretary and interpreter to the military attaché at the United States Embassy in Spain and France in 1918–19. When he returned to the states he studied law at St. Louis University and later attended the University of Texas law school. He passed the bar examination on June 9, 1924. By 1930 Gonzales had also worked with the Bexar County district attorney and become familiar with crime cases.
He began working for Mexican-American civil rights while he was employed at the Patterson and Love firm. He played a key role in the founding of La Liga Protectoria Mexicana (see MEXICAN PROTECTIVE LEAGUE) around 1917, the Asociación Jurídica Mexicana (a legal-assistance organization) in 1921, and the Sons of Texas in 1922. Gonzales also served as vice president of the Order of Knights of America in 1927, wrote the constitution and charter for the Mexican Chamber of Commerce in 1928, and acted as secretary at the founding convention of the League of United Latin American Citizens on February 17, 1929. He was active in LULAC for many years. In 1931 and 1932 he participated in the Del Rio ISD v. Salvatierra case. He became the third LULAC president in 1931. He also worked with the "Flying Squadron," a San Antonio LULAC organizing team, in the 1930s, and served as national executive secretary in LULAC under the George I. Sánchez and Ben Osuna administrations (1941–43). Gonzales worked as legal advisor for the Mexican Consulate from 1926 to 1958 and held several diplomatic positions with Mexico and Guatemala. He was a proponent of the Good Neighbor Commission and Pan-Americanism.
He was one of only a few Mexican Americans to seek political office in San Antonio in the early twentieth century. In 1930 he ran as a Democrat for the state legislature, and he made a name for himself as a fighter of machine politics. In 1954 he was elected to the San Antonio Union Junior College District Board of Trustees, a position he held until 1978. He wrote for such periodicals as El Luchador, OKA News, LULAC News, Alma Latina, and the Texas Outlook. He was a member of the Methodist Church, the Perfect Union Masonic Lodge, the Shriners, and the Lion's Club and served as a scoutmaster. The Latin American Sports Association named a trophy in his honor, and when he retired from the San Antonio Union Junior College District Board of Trustees the science building at San Antonio Junior College was named after him. In 1976 he was chief of the district attorney's grand jury. Gonzales died in San Antonio on June 12, 1986, and left a legacy throughout the Southwest as a defender of the rights of Mexican Americans. His papers are located in the Nettie Lee Benson Latin American Collection at the University of Texas at Austin.