Army General Martin Dempsey will become the next chairman of the Joint Chiefs of Staff after the Senate confirmed his appointment.
Dempsey, 59, will replace Admiral Mike Mullen, who has held the post since 2007, as the highest-ranking US military officer at the end of September.
Defense Secretary Leon Panetta, who assumed office earlier this year after serving as CIA director, welcomed the Senate's confirmation of Dempsey and of Admiral James Winnefeld as the new vice chairman.
"I am thrilled these two great Americans will soon join me in leading the finest military in the world," Panetta said in a statement.
"They bring with them immense intellect, proven leadership and far-reaching strategic vision, and I know that both the president and I will greatly benefit from their candid advice and counsel."
The three will work closely in the coming months as Washington seeks to trim defense spending as part of a larger effort to rein in the country's deficit as it winds down costly wars in Iraq and Afghanistan.
The Senate also confirmed General Ray Odierno as Army chief of staff and Admiral Jonathan Greenert as chief of naval operations.