In 1948, Stevenson was elected governor of Illinois, defeating incumbent governor Dwight H. Green in an upset. As governor, Stevenson reformed the state police, cracked down on illegal gambling, improved the state highways, and attempted to cleanse the state government of corruption. Stevenson also sought, with mixed success, to reform the Illinois state constitution and introduced several crime bills in the state legislature.
In 1952 and 1956, Stevenson was chosen as the Democratic nominee for president but was defeated in a landslide by Eisenhower both times. In 1960, he unsuccessfully sought the Democratic presidential nomination for a third time at the Democratic National Convention. After President John F. Kennedy was elected, he appointed Stevenson as the United States ambassador to the United Nations (UN). Two major events Stevenson dealt with during his time as UN ambassador were the Bay of Pigs Invasion of Cuba in April 1961 and the Cuban Missile Crisis in October 1962. He was still serving as UN ambassador when he suffered a heart attack during a visit to London on July 14, 1965, dying later that day at the age of 65. He is buried in Evergreen Cemetery in his hometown of Bloomington, Illinois.
Adlai was an active member of the Bloomington Rotary in Bloomington, IL.
