Adlai Stevenson is best remembered for his performances at the United Nations, where he served as an ambassador during the Kennedy administration. He had grown into the role of elder statesman of the Democratic part by then, but along the way the governor of Illinois took a few runs at the White House.
In 1952 President Truman suggested he run, but Stevenson said he would run for re-election in Illinois. He was drafted into running by delegates at the national convention. He had the misfortune of running against Gen. Eisenhower, who won the election easily. Stevenson could only carry 9 states against the war hero.
After that defeat he travelled abroad and returned to the national stage in 1956. Stevenson campaigned hard in 1956, but the field of Democrats was narrow. No one wanted to lose to Eisenhower. Stevenson took the job and promptly lost again, earning even fewer electoral votes in 1956 than four years previous.
Which explains the disappearing hair.
He would not run again, but hoped that delegates would push him forward once more. They did not, turning instead to John Kennedy. Stevenson campaigned for the Kennedy-Johnson ticket and served at the U.N. until his death, when he suffered heart failure in London in 1965.