Dempsey, whose pick requires US Senate confirmation, would replace Adm. Mike Mullen as chairman of the Joint Chiefs of Staff when he steps down on Oct. 1. At a White House ceremony, Obama hailed Dempsey as "one of our nation's respected and combat-tested generals."

Obama announced the choice for the high-profile post just before heading to Arlington Cemetery outside Washington for a wreath-laying and remarks to honor America's war dead on Memorial Day. The nomination was the latest move in an overhaul Obama's national security team.