Robert Henry Winborne Welch, Jr., was born on December 1, 1899, in Chowan County, North Carolina. He finished high school at the age of twelve and graduated from the University of North Carolina at the age of seventeen. After spending two years at the United States Naval Academy in Annapolis, Maryland, and two years at Harvard Law School in Cambridge, Massachusetts, Welch left the academic life and in 1921 founded the Oxford Candy Company in Brooklyn, New York. In 1932 he joined the staff of E.J. Branch and Sons, which was at the time the largest candy manufacturer in the United States. Two years later he became the sales manager for the James O. Welch Company, which was owned by his brother James. While at the Welch Company he developed several well known candies, including Sugar Daddies, Sugar Babies, and Junior Mints. He retired from the candy business in 1956.

Welch ran for political office once, when he campaigned unsuccessfully for the Republican nomination for lieutenant governor of Massachusetts in 1950. In 1958, he and eleven other men founded the John Birch Society, which was dedicated to the goals of less government, more individual responsibility, and a better world. He served as the head of the Society from its founding until 1983, when he retired because of ill health. He passed away on January 6, 1985. At the time of his death he was survived by his wife Marian Probert Welch, whom he married in 1922; two sons, Hillard Walmer Welch and Robert Welch, III, and six grandchildren.

Harold Lord Varney (1893-1984) was an American author and magazine editor. Although he had been a member of the International Workers of the World (I.W.W.) as a young man, he later defended Benito Mussolini and was an associate editor of the fascist magazine. He was an editor and contributor to when it was known, especially during the 1950s, for publishing articles that espoused anti-Semitism and racism. Varney founded the Committee on Pan American Policy, which later became part of the John Birch Society.

The John Birch Society was founded in Indianapolis, Indiana, on December 9, 1958. Robert Welch, Jr. (1899–1985), a retired candy manufacturer, led the organization from its founding until his retirement in 1983. The original twelve founding members included Fred Koch (1900-1967), founder of Koch Industries, and Robert Waring Stoddard (1906-1984), president of Wyman-Gordon, a manufacturer of complex metal components. The Society's purpose was to combat communism and promote various ultraconservative causes. It was named in honor of John Birch, an American Baptist missionary and United States Army intelligence officer who was killed by Chinese communists on August 25, 1945, making him, in the Society's view, the first casualty of the Cold War. Although it does not release membership numbers, the Society was estimated to have between 60,000 and 100,000 members at the height of its activities during the 1960s. By 1985 the membership was estimated to be about 50,000.

The Society has local chapters in all fifty states. It uses grassroots lobbying, educational meetings, petition drives and letter-writing campaigns to gain members and influence public policy. Because of its belief in limited government and its belief in an international conspiracy whose goal is to replace Western nations with a one-world socialist government, the Society has opposed any trade or diplomatic relations with communist countries as well as American membership in the United Nations. In addition, the Society has opposed the federal income tax and the Federal Reserve system, Social Security, the Medicare program, the creation of the Occupational Health and Safety Administration (OSHA), the transfer of control of the Panama Canal from the United States to the Republic of Panama, the Civil Rights Movement, sex education in public schools, and efforts to add fluoride to water supplies. While it supports the American military, it has opposed American military intervention overseas. The Society has operated Summer Youth Camps across the United States and has produced radio programs, newspapers columns, and films.

Among the many national campaigns that the Society has organized or supported are the campaign to impeach Chief Justice Earl Warren in the 1960s, The Movement to Restore Decency (MOTOCREDE), Promote Our Wonderful Energy Resources (POWER), the Support Your Local Police and Keep Them Independent! (SYLP) campaign, whose purpose was to oppose any state or federal control of local police departments, especially with regard to enforcing civil rights laws; Truth about Civil Turmoil (TACT), To Restore American Independence Now (TRAIN), Tax Reform Immediately (TRIM), and the National Right to Work Committee, which opposes compulsory union membership as a condition of employment.

The business activities of the Society are part of the General Birch Services Corporation. They include the American Opinion Speakers Bureau, the American Opinion Book Division, John Birch Society Features, and Western Islands publishing. , a transcript of Welch's presentation at the organization's founding meeting in 1958, is published by Western Islands. The Society has also published several periodicals. and merged in 1985 to become. was a syndicated weekly column for newspapers. The Society's is a monthly newsletter for members. is a transcript of a daily five-minute radio commentary written and narrated by Alan Stang and produced by John Birch Society Features. The is produced by MOTOCREDE. In addition, the Society produced a syndicated fifteen-minute radio program called "Are you listening, Uncle Sam?"

The Society was involved in two notable controversies. In the first, Robert Welch implied, first in a letter and then in his book, that Dwight D. Eisenhower was a tool of the "Communist Conspiracy." This caused him to lose the support of many notable conservatives such as William F. Buckley, Jr., and Barry Goldwater, a Republican Senator from Arizona who was his party's presidential candidate in 1964.

In 1974, the Society lost an important free speech case in the Supreme Court (Gertz v. Robert Welch, Inc.). The case was brought by Elmer Gertz, a lawyer who had sued the Society for libel. Gertz had been hired by the family of Ronald Nelson to represent them in a civil action against a police officer, Richard Nuccio, who shot and killed Nelson. The Society accused Gertz of orchestrating Nuccio's criminal conviction for second-degree murder and of belonging to various communist front organizations. The Court held that a state may allow a private figure such as Gertz to recover actual damages from a media defendant without proving malice.

In 1989, the Society closed its West Coast office in San Marino, California, and moved its headquarters from Belmont, Massachusetts, to Appleton, Wisconsin. Its new chief executive officer at the time, G. Allen Bubolz, owned several businesses in Appleton, which is also the home town of the late Republican Senator Joseph McCarthy, known for his anti-communist crusade in the 1950's.

In 2010 the Society co-sponsored the Conservative Political Action Conference (CPAC), an annual round table of prominent conservatives and figures from the Republican Party.