Sidney 'Sid' McMath was born in Columbia County, Arkansas. McMath graduated from the University of Arkansas law school in 1936.

During World War II McMath served in the United States Marine Corps and rose to the rank of Lieutenant Colonel. He took part in the battles of the Pacific Theater including the Battle of Bougainville, directing the Battle of Piva Forks, the determinative action. McMath won the Silver Star and the Legion of Merit. He served two reserve tours in Vietnam with the 3d Marine Division as a Major General.

When McMath returned from the war to Hot Springs, Arkansas he and other veterans became disenchanted with the political system and banded together to fight corruption in the city government which was dominated by illegal gambling interests. Hot Springs at the time was a national gambling mecca frequented by organized crime figures from Chicago, New York and other metropolitan areas. Casinos flourished along with illicit off-track betting. Mobsters maintained control of the local government through the time honored technique of purchasing and holding hundreds of poll tax receipts, often in the names of deceased or fictitious persons, which would be used to cast multiple votes in different precincts. Law enforcement officers were on the payroll of the local "organization" headed by long serving Mayor Leo McLaughlin. A sheriff who attempted to enforce the state's anti-gambling laws was murdered in the late 1930's. No one was ever charged in the killing. McMath's "GI Ticket", except for McMath, himself, who as a district candidate carried neighboring Montgomery County by a sufficient majority to win the nomination for prosecutor, were defeated in the Democratic primary. However, they resigned from the party and ran again as independents in the 1946 general election after McMath persuaded a Federal judge to toss out the fraudulent poll tax receipts. All won their offices.

McMath served as prosecuting attorney for the 18th Judicial District [Garland and Montgomery Counties] counties starting in 1947. A number of minor offenders were convicted of racketeering, but Mayor McLaughlin was acquitted by a Montgomery County jury. However, the back of his political organization was broken. With the development of Las Vegas in the years afterward, Hot Springs lost its premier gaming status, although there was a brief small-scale casino revival during the administration of Governor Orval Faubus (1955-1967). These operations were closed by Republican governor Winthrop Rockefeller, Faubus' successor, in 1967.

McMath was elected Governor of Arkansas in 1948 and entered office in early 1949. He was reelected in 1950.

McMath's administration focused on infrastructure improvement including new highways and roads and a medical center in the capital city. McMath supported anti-lynching statutes and appointed African-Americans to state boards. His administration improved the state's educational system, including the building of the University of Arkansas Medical School which was financed with a two-cent tax on cigarettes--a major innovation at the time. McMath often stated that he considered UAMS, now recognized as one of the nation's leading teaching and research institutions, to have been his greatest accomplishment. McMath also reformed the state's mental health system and increased the minimum wage.

McMath was defeated in the 1952 election. He ran unsuccessfully for the US Senate in 1954 and again for Governor in 1962.

He returned to the practice of law and over the next half century became one of the leading personal injury trial attorneys in the United States. His cases set a number of legal precedents, including a woman's right to recover for the loss of her husband's consortium (an element of damage previously limited to men), manufacturers' responsibility for harm caused by defective products and negligent advertising encouraging their misuse, the chemical industry's liability for crop and environmental damage, and the right of workers to sue third party suppliers for job injuries. He and his partner Henry Woods, who had served as his gubernatorial chief of staff and later became a Federal judge, became nationally known for their effective use of powerful demonstrative evidence such as detailed models of accident scenes and cut-away charts of the human anatomy. In 1976 he was elected president of the International Academy of Trial Lawyers, an exclusive group limited to the 500 top barristers in the world. He wrote a memoir entitled Promises Kept (University of Arkansas Press, 2003, ISBN 1-55728-754-6) detailing his rural upbringing and his years as governor and in military service. An appendix discusses his more interesting and significant cases from the layman's point of view.

McMath remained active, speaking at Arkansas schools and events and supporting local civic organizations, including the Scottish Rite Masons who awarded him its highest honor of the Grand Cross and the Lions World Services for the Blind, whose training school in Little Rock he completed in 1999 following the loss of his vision due to macular degeneration. A video commercial featuring McMath has been aired nationally by the school in recent years.

In a 1999 opinion poll of Arkansans McMath polled number four on the list of top Arkansas Governors of the 20th century. In a December 2003 forum of historians and journalists sponsored by the Old State House Museum, there was a consensus that McMath's early commitment to civil rights, particularly his support of President Truman in the 1948 presidential election against Dixiecrat Strom Thurmond, the abolition of the so called "white primary" in Arkansas (1949), the opening of the state's medical and law schools to African Americans (1949), McMath's relentless opposition to segregationist governor Orval Faubus, a former McMath ally, could eventually raise him to first place.

One participant at a Southern Arkansas University forum on McMath held November 3, 2003 in Magnolia, Arkansas stated: "When Sid McMath stood for civil rights in the 1940s and 1950's he stood virtually alone among the South's political leaders, most of whom were waving the bloody shirt. By the 1970s every Southern pol was supporting full citizenship for African Americans. It was by then politically correct. But for McMath, it took unprecedented courage. And in fact it cost him whatever chance he had to salvage his political career. He certainly deserves a chapter in the next "Profiles in Courage". He was a true hero, not only to the South, but also to the Nation. He ranks with [Illinois governor] John Peter Altgeld and [Texas reform governor] James Stephen Hogg as the greatest of the American governors whose stands on principle undoubtedly cost them a genuine chance to contend for the presidency. His life can be summed up in one word: Valor."

McMath’s stature as a productive political leader has been significantly increased in light of his highway department's paving of more hard surface roads than any previous administration (and more than those paved by any other Southern state during his tenure) and his politically fatal war against Mid South Utilities, the dominant political force in state politics at the time, which operated in Arkansas as Arkansas Power and Light Co., or "AP&L". The corporation and its affiliates opposed extension of REA electrical power to rural areas, which they saw as a rich territory for their own eventual expansion. Fewer than half of Arkansas farm homes had electricity in 1948. REA-affiliated cooperatives, however, were able to open service to those areas by 1956 as the result of Co-op enabling legislation enacted by Congress in large part at McMath's behest.

Mid South and its allies combined to defeat McMath in his 1952 re-election bid and in his 1954 effort to unseat then-Senator John L. McClellan. McClellan, who maintained a lucrative law practice with Mid South's chairman and general counsel, referred to the REA coops as "communistic" during the campaign, which was conducted at the height of the "red-scare" attendant upon assertions by the late U.S. Senator Joseph McCarthy (R-Wis) of communist influence in the Truman administration. McClellan was the ranking member of the Army McCarthy subcommittee whose hearings were televised live during the lead up to the election. McClellan narrowly defeated McMath in an election now recognized to have been marked by widespread fraud. For example, record numbers of black voters, for whom McMath had only five years before secured the right to vote in Democratic primaries, were trucked to the polls in Eastern Arkansas by McClellan supporters among the planters of that region who held their workers' poll tax receipts. McMath lost some of those precincts by better than 4 to 1 margins.

Allegations of corruption in McMath's highway department, brought by a grand jury dominated by utility allies, were eventually proven unfounded in three separate proceedings. Two grand juries returned no indictments, but a third on which several Mid South managers served, returned three. All of the accused were acquitted. There was no allegation of personal wrongdoing by McMath. However, the allegations against his administration dogged McMath for the rest of his life and his biography includes a chapter refuting the charges and chastising his opponents for abusing the judicial system to fabricate them.

Sidney Sanders McMath died at his home in Little Rock, Arkansas on Saturday, October 4, 2003. He had had been released from the hospital the previous Wednesday after being treated for an irregular heartbeat. He is survived by his wife, Betty Dorch Russell McMath, three sons: Sandy, Phillip and Bruce McMath; two daughters, Melissa Hatfield and Patricia Bueter; ten grandchildren and one great grandchild. His first wife and childhood sweetheart, Elaine Braughton McMath, died in 1942. His second wife, of 49 years, Anne Phillips McMath, died in 1994.

Sid McMath Avenue in Little Rock is named for him and the Little Rock Public Library recently dedicated a new branch in his honor.