He attended the University of Illinois, graduating with a B.A. in history in June 1955. He then spent several years at Columbia University, earning an M.A. in February 1957, and a Ph.D. in June 1964. While working on his Ph.D., he was a history instructor at Columbia.

From 1964 until 1994 Dallek advanced from assistant to full professor of history at UCLA. By 1966, he was a graduate advisor in the Department of History at UCLA and served in that position for two years. From 1972 to 1974, he served as Vice-Chair of the UCLA Department of History. From 1981-1985, he was a Research Associate at the Southern California Psychoanalytic Institute. In 1993, he was a visiting professor at the California Institute of Technology, and from 1994 to 1995 he was the Harmsworth Visiting Professor at the University of Oxford. In 1995 he was awarded an honorary M.A. by Oxford University for his work there. Since 1996 he has been a Visiting Professor at the LBJ School of Public Affairs, University of Texas and a Professor of History at Boston University. In 2004 and 2005, he was Montgomery Fellow and a visiting professor in the history and government departments at Dartmouth College. Since 2007, he has taught courses at Stanford University in California.

Books

• Democrat and Diplomat: The Life of William E. Dodd (New York: Oxford University Press, 1968)
• 1898: McKinley's Decision - The United States Declares War on Spain (New York: Chelsea House, 1969)
• The Roosevelt Diplomacy and World War II (New York: Holt, Rinehart and Winston, 1970)
• Western Europe (New York: Chelsea House, 1973)
• Franklin D. Roosevelt and American Foreign Policy, 1932-1945 (New York: Oxford University Press, 1979)
• The American Style of Foreign Policy: Cultural Politics and Foreign Affairs (New York: Knopf, 1983)
• Ronald Reagan: The Politics of Symbolism (Cambridge, MA: Harvard University Press, 1984, ISBN 978-0-674-77941-9)
• Lone Star Rising: Lyndon Johnson and his Times, 1908-1960 (New York: Oxford University Press, 1991)
• Franklin D. Roosevelt as World Leader: An Inaugural Lecture Delivered before the University of Oxford on 16 May 1995 (New York: Clarendon Press, 1995)
• Hail to the Chief: The Making and Unmaking of American Presidents (New York: Hyperion, 1996)
• Flawed Giant: Lyndon Johnson and his Times, 1961-1973 (New York: Oxford University Press, 1998)
• John F. Kennedy, 1917-1963 (Boston: Little, Brown, and Co., 2003)
• Lyndon B. Johnson: Portrait of a President (New York: Oxford University Press, 2004)
• Lessons from the Lives and Times of Presidents (Richmond, VA: University of Richmond, 2004)
• Let Every Nation Know: John F. Kennedy in His Own Words (with Terry Golway) (Naperville, IL: Soursebooks,Inc., 2006)
• Nixon and Kissinger: Partners in Power (New York: HarperCollins, 2007)
• Harry S. Truman (Times Books, 2008, ISBN 9780805069389)

Journal articles

• 'Franklin Roosevelt as world leader', The American Historical Review, 76 (1971): 1503-1513
• 'National mood and American foreign policy: a suggestive essay', American Quarterly, 34 (1982): 229-261
• 'Lyndon Johnson and Vietnam: the making of a tragedy', Diplomatic History, 20 (1996): 147
• 'Tales of the tapes', Reviews in American History, 26 (1998): 333-338

Essays in edited volumes

• 'American perceptions of the Soviet Union', in Abbott Gleason (ed.), Cold War-Cold Peace: Soviet American Relations, 1933-1983 (Boston: Beacon Press, 1975)
• 'Triumphant America in a shaken world', in Sanford J. Ungar (ed.), Estrangement: America and the World(New York: Oxford University Press, 1985)

He appeared on The Daily Show in July 2007. He has made numerous appearances on CNN and on public television and radio.