Homeland Security Secretary Janet Napolitano is resigning her post to assume the presidency of the University of California system.
Napolitano, former governor and attorney general of Arizona, told senior members of her DHS staff Friday morning.
She was named Homeland Security chief by President Obama in 2008.
Napolitano will preside over 10 universities.
"The opportunity to work with the dedicated men and women of the Department of Homeland Security, who serve on the front lines of our nation's efforts to protect our communities and families from harm, has been the highlight of my professional career," she said in a statement.
"After four plus years of focusing on these challenges, I will be nominated as the next president of the University of California to play a role in educating our nation's next generation of leaders.
"I thank President Obama for the chance to serve our nation during this important chapter in our history," Napolitano said, "and I know the Department of Homeland Security will continue to perform its important duties with the honor and focus that the American public expects."
Under her tenure, DHS implemented a widespread policy of using prosecutorial discretion when arresting immigrants in the country without permission, saying her department needed to focus its scarce resources on criminals and those who posed a threat to public safety and national security. She also helped establish a plan to provide temporary relief from deportation for thousands of young immigrants who arrived in the United State illegally and who don't have legal status.
From the Los Angeles Times:
UC officials believe that her Cabinet experiences -- which include helping to lead responses to hurricanes and tornadoes and overseeing some anti-terrorism measures -- will help UC administer its federal energy and nuclear weapons labs and aid its federally funded research in medicine and other areas.
President Barack Obama issued a statement commending Napolitano for what he called "her outstanding work on behalf of the American people over the last four years."
Associated Press contributed to this article.