Franklin D. Roosevelt
In 1933, Roosevelt came to office in the Great Depression, with one in four workers idle, more than 80 percent of the stock market's value gone, farmers destitute, urban dwellers in bread lines, and banks failing at an alarming rate, eliminating the savings of millions. Fellow Democrats controlled the House and Senate.
He immediately declared a temporary closure of banks to stop panic withdrawals, called a special session of Congress and won passage of a law to stabilize the banking system.
He came forward with a flurry of legislation that set the pillars of the New Deal in place within his first 100 days, "the most concentrated period of U.S. reform in U.S. history," said Alan Brinkley and Davis Dyer in "The Reader's Companion to the American Presidency." FDR threw public funds behind industrial recovery, agricultural renewal and public works.
His burst of productivity gave rise to American history's 100-day benchmark for new presidents.
John F. Kennedy
A master orator, JFK was not a high achiever in his first 100 days in 1961, a period marked by the bungled Bay of Pigs invasion of Cuba by U.S.-trained Cuban exiles and the Soviet Union's launch of the first human into outer space on April 12.
Kennedy proved more sure-footed in Cold War brinkmanship that came later, declaring a quarantine on Soviet shipping to Cuba to prevent the establishment of missile bases that were able to strike the U.S. The Soviets relented in 1962, defusing a crisis that had brought the nuclear powers perilously close to war.
Kennedy's first official act, on Jan. 21, was to issue an executive order directing a doubling of the amount of surplus food that was being distributed to needy families.