Janet Ann Napolitano (born November 29, 1957) is the third United States Secretary of Homeland Security. She assumed the job on January 21, 2009, and is the first woman to serve in that office. An American politician from the Democratic Party, Napolitano was serving as governor of the state of Arizona when designated by then-President-elect Barack Obama to be his Secretary of Homeland Security. She was confirmed by the Senate and sworn in one day after Obama's inauguration. She was chair of two state Governors' associations and was named by Time as one of the top five governors in 2005. Prior to the governorship, she served as Arizona Attorney General from 1999 to 2002.

Napolitano was first elected governor in 2002, and was re-elected in 2006. She was Arizona's third female governor, and the first woman to win re-election. Napolitano was succeeded by Arizona's Secretary of State, Jan Brewer, who became Arizona's fourth female governor and third consecutive female governor.

Janet Ann Napolitano was born on November 29, 1957 in New York City, the daughter of Jane Marie (née Winer) and Leonard Michael Napolitano, who was the Dean of the University of New Mexico School of Medicine. She is of Italian heritage and is a Methodist. She was the oldest of three children; she has a younger brother (Leonard Jr.) and a sister (Nancy). She was raised in Pittsburgh, Pennsylvania, and Albuquerque, New Mexico, where she graduated from Sandia High School in Albuquerque in 1975 and was voted Most Likely to Succeed. She graduated from Santa Clara University in Santa Clara, California, where she won a Truman Scholarship, and was valedictorian. She then received her Juris Doctor (J.D.) from the University of Virginia School of Law. After law school she served as a law clerk for Judge Mary M. Schroeder of the United States Court of Appeals for the Ninth Circuit, and then joined Schroeder's former firm, the Phoenix law firm Lewis and Roca.