Napolitano, 51, was named by U.S. President-elect Barack Obama to his Cabinet Monday in Chicago.
As Arizona governor, Napolitano called in 2006 for the federal government to pay for the deployment of the National Guard along the state's porous border with Mexico, a move ultimately approved by U.S. President Bush. As homeland security leader, Napolitano will be in a position to expand some of the experimental programs she's been using to secure the Arizona border on a national level, immigration analysts said.
After serving as U.S. attorney for Arizona, Napolitano won the state's 2002 gubernatorial election with 46 percent of the vote. She became the first woman in U.S. history to be elected a governor to succeed another elected female governor.
In 2006 she was mentioned as a possible running mate for Democratic U.S. presidential nominee Sen. John Kerry of Massachusetts, but instead won a second Arizona gubernatorial term in a landslide.