The International Brotherhood of Teamsters formed in 1903 when the American Federation of Labor merged two rival groups of wagon drivers, who controlled the final mile between rail depots and businesses. First president Cornelius Shea fell after the failed 1905 Chicago strike, when 25,000 Teamsters backed locked-out tailors at Montgomery Ward and the press reported Shea living in a brothel and throwing parties on union funds. Daniel J. Tobin led from 1907 to 1952, curbing wildcat strikes and pushing locals into joint councils and master agreements. Membership rose from 82,000 in 1932 to 530,000 in 1941, driven partly by organizers Tobin disliked, including the Trotskyists behind the 1934 Minneapolis strike, who built the Central Conference of Teamsters, and Dave Beck’s Western Conference.

Beck took the presidency in 1952, and Jimmy Hoffa brought organized crime onto the national stage, working with mobster Johnny Dio in 1956 to charter paper locals with no members to win convention votes. The McClellan Committee, with Robert F. Kennedy as chief counsel, found Beck had taken a $300,000 interest-free loan from union funds; Beck took the Fifth 117 times, the AFL-CIO expelled the union in 1957, and the hearings led to the Landrum-Griffin Act of 1959. Hoffa’s 1964 National Master Freight Agreement gave the union enormous power, while the Central States Pension Fund financed Las Vegas casinos. Hoffa was convicted of witness tampering, imprisoned in 1967, pardoned by Nixon and vanished in 1975. Trucking deregulation in 1979 cost 30 percent of freight Teamsters their jobs.

• Franklin D. Roosevelt gave his 1944 Fala speech at the Teamsters convention.
• Pension fund money helped build Caesars Palace, the Stardust and the Dunes.
• A 1989 RICO consent decree brought direct elections, and reformer Ron Carey won in 1991 with backing from Teamsters for a Democratic Union.
• A $36 billion federal grant in 2022 rescued the Central States Pension Fund for about 350,000 workers and retirees.
• In 2024 Sean O’Brien spoke at the Republican National Convention, and the union endorsed no presidential candidate for the first time since 1996.