Alejandro Nicholas Mayorkas was born on November 24, 1959, in Havana, Cuba. His father was Cuban, and his mother was Romanian. She had fled to Cuba during the rise of fascism in Europe before World War II. When Fidel Castro took control of Cuba in 1960, the Mayorkas family left the country, living briefly in Miami, Florida, before settling in Los Angeles, California. Alejandro and his sister grew up in Beverley Hills, California. He graduated from the University of California at Berkeley in 1981, and then attended Loyola Law School, graduating in 1985. 

Mayorkas began his law career in private practice before joining the US Attorney’s office in Los Angeles in 1989. In 1998, President Bill Clinton nominated Mayorkas to be the youngest US Attorney. After Clinton left office, Mayorkas left government and returned to private practice during the years of the George W. Bush administration. When President Barack Obama took office in 2009, he nominated Mayorkas as the director of the US Citizenship and Immigration Services (USCIS). In that position, he implemented the Deferred Action for Childhood Arrivals (DACA) in 2012. 

In 2013, President Obama nominated Mayorkas as deputy secretary for the Department of Homeland Security. He served in that office until 2016, before returning to private law practice. When Joe Biden was elected president, he announced his intention to appoint Mayorkas as secretary of the Department of Homeland Security. The US Senate confirmed him by a vote of 54 to 43 on February 2, 2021, and he was sworn in that same day as the first Latino to serve as secretary of DHS.