The council replaces its preceding organisation, the UN Commission on Human Rights.
'Advancing US interests'
Susan Rice, Washington's ambassador to the UN, said that membership of the council would be "a tool to advance our interests".
"We don't view it as legitimising the council. We will stand up and forcefully lead on those issues that we care most deeply about," she said.
Ban Ki-moon, the UN secretary-general, issued a statement welcoming the US decision, saying it was a concrete example of the US commitment to a "new era of engagement" at the UN.
The US participated in the council on March 4 for the first time, urging it to address all violations of rights and to not just focus on Israel - five out of 10 special council sessions have been called to discuss Israeli policies towards Palestinians and Lebanon.
Rice said the US felt the council "should be a venue for dealing with the most egregious instances of human rights abuses".
"We are running for a seat on the council because we believe that human rights are universal, they need to be universally respected," she said.