Bruised by the war in Iraq and now Hurricane Katrina, Bush made a rare visit on Friday to the State Department to watch the 48-year-old Hughes sworn in as undersecretary of state for public diplomacy and public affairs with ambassador-level rank.
He called her mission an "incredibly important" dimension to the so-called war on terror, adding "we must defeat the terrorists on the battlefield but also on the battlefield of ideas".
Hughes, who has been at Bush's side since his days as Texas governor and was instrumental in his two successful runs for the presidency, pledged to bridge the gap between the US and hostile parts of the world.
"I believe there is no more urgent challenge for America's national security and for a more peaceful future for all the world's children than the need to foster greater respect, understanding and a sense of common interest and common values," she said.
Hughes will make a first "listening tour" of the Middle East at the end of this month, also stopping in some European capitals, said a State Department official, who asked not to be named. Her precise itinerary was not available.
The March 2003 invasion of Iraq, the scandal over the abuse of Iraqi inmates at the Abu Ghraib prison and other incidents have taken a huge toll on US ties with the Muslim world.
Scenes of chaos and neglect in the aftermath of Hurricane Katrina also produced expressions of ridicule in Muslim countries, where commentators said they showed the United States to be a paper tiger unable even to take care of its own.
Hughes, who began work in her new post four weeks ago, acknowledged to reporters on Thursday that the early federal failure to speed troops and relief supplies had hurt the effort to burnish the US image abroad.
"It's unfortunate. The whole world has been watching," she said. "It's not just the world, it's also our fellow Americans - we recoil at the idea that the poorest, the most elderly, the sickest weren't able to get out."