Leon Edward Panetta was born on June 28, 1938, in Monterey, California. His parents were both immigrants from Italy. He was raised in the Monterey area and attended Santa Clara University, graduating in 1960 with a degree in political science. In 1963, he graduated with a law degree from Santa Clara University School of Law and served in the U.S. Army until 1965.

He began his political career as a legislative aid for Republican Senator Thomas Kuchel of California in 1966. In 1969, Panetta went to work for the Department of Health, Education, and Welfare in the administration of President Richard Nixon. He was appointed head of the U.S. Office for Civil Rights but left in 1970 after disagreeing with the administration's slow approach to school desegregation. He returned to California and practiced law.

After switching from a Republican to a Democrat, Panetta was first elected to the U.S. House of Representatives in 1976 and served until 1993. He left office to join the administration of President Bill Clinton as director of the Office of Management and Budget (OMB). He then became chief of staff for Clinton in 1994. When he left the Clinton White House in 1997, he went back to his home state and established the Panetta Institute for Public Policy at California State University, Monterey Bay. 

In 2009, President Barack Obama nominated Panetta to be director of the Central Intelligence Agency (CIA). As director of the CIA, Panetta oversaw the operation that found and killed Osama bin Laden, the Al Qaeda leader who masterminded the attacks of September 11, 2001. President Obama then appointed Panetta as secretary of Defense in 2011; the U.S. Senate unanimously confirmed his nomination. Secretary Panetta oversaw the end of the Iraqi War, extended benefits to same sex couples in the military, and lifted the ban on women in combat. After leaving the Obama administration, he returned to California and the Panetta Institute.