Alan D. Bersin was born in Brooklyn, New York on October 15, 1946. He graduated from Harvard University, magna cum laude, with an A.B. in Government in 1968 and became a member of Phi Beta Kappa National Honors Society. He played on the Harvard Crimson football team and in 1995 was inducted into the Harvard Varsity Club Hall of Fame. From 1968 to 1971, Bersin attended Balliol College, Oxford as a Rhodes Scholar where he met future President Bill Clinton. In 1974, he earned a J.D. from Yale Law School.

After graduating from Yale, Bersin served as special counsel to the Los Angeles Police Commission. He then joined the prestigious Los Angeles law firm Munger, Tolles and Olson in 1975 where he specialized in RICO, securities, insurance and commercial litigation. Later, he became a senior partner and is credited for his role in developing Munger, Tolles and Olson's paralegal program and for chairing the committee which oversaw the firm's pro bono legal services program.

Bersin taught law briefly at the University of San Diego before he was appointed U.S. Attorney for the Southern District of California by President Clinton in 1993. He was awarded a degree of Doctor of Laws (Honorary) by the University of San Diego in 1994, and then again by California Western School of Law in 1996. From 1995 to 1998, he served as Special Representative for the Southwest Border and oversaw law enforcement along the U.S.-Mexico border. In this capacity, Bersin implemented "Operation Gatekeeper" which fortified the border near San Diego, shifting the traffic of illegal immigrants to the deserts of Arizona and New Mexico.

Between 1998 and 2005, Bersin served as Superintendent of Public Education for San Diego City Schools, the eighth largest urban school district in the United States. While superintendent, he initiated a major reorganization of the school district which included the controversial "Blueprint for Student Success" and the creation of the Institute for Learning. Bersin also served between 2000 and 2003 as a member of the California Commission on Teacher Credentialing and chaired the Commission for a two-year term.

In 2005, Bersin accepted Governor Arnold Schwarzenegger appointment to become California's Secretary of Education. He held this post until 2006, when he was appointed Board Chairman of the San Diego County Regional Airport Authority.

In April, 2009, Homeland Security Secretary Janet Napolitano announced the appointment of Bersin as Department of Homeland Security Assistant Secretary for International Affairs and Special Representative for Border Affairs. Later in March 2010, he was selected by President Barack Obama to serve as Commissioner of U.S. Customs and Border Protection.