Arriving the first day on his new job, Kerry told State Department employees he will continue President Obama's push to make the world a safer place.
"This president's vision, and what he has implemented through your efforts over the course of the last years without any question, has restored America's reputation and place in the world," Kerry said.
He said that reputation can help empower people.
"We get to try to make peace in the world, a world where there is far too much conflict, far too much killing. There are alternatives," Kerry said. "We get to lift people out of poverty. We get to try to cure disease. We get to try to empower people with human rights. We get to speak to those who have no voice.
Human rights were a focus of President Obama's first term, including stopping violence against women in the Democratic Republic of Congo. Human Rights Watch deputy Washington director Sarah Margon says Kerry can do more.
"I'd like to see in the next Obama administration it become an even more central tenet particularly on some of the central national security issues that the administration is going to have to address," Kerry said.