"This campaign was and will remain the great honor of my life," McCain said in front of a crowd gathered at the Arizona Biltmore hotel.
The senator's second try for the White House fared better than his first but not good enough to turn the tide of Barack Obama's message of change.
"I urge all Americans who supported me to join me in not just congratulating him [Obama] but offering our next president our good will and earnest effort to find ways to come together," McCain said.
Senator McCain's path to victory was a narrow one, blocked early by defeats in Pennsylvania and Ohio.
In the final days of the race, the 72-year-old senator outpaced his younger rival by traveling more miles, visiting more states and campaigning longer hours. Still, it wasn't enough.
"I think John is always concerned with how best he can advance the cause of state and nation. He's not concerned with John McCain as much as he is just concerned with those bigger ticket issues, " said Retired Major Gen. John Borling, who was a POW with John McCain.
For all the disappointment over the loss, McCain supporters gave strong applause when he mentioned the historical significance of electing the nation's first African-American president.
Some who poured their hearts and souls into the McCain campaign conceded the nation's mood was not on their side.
"You always have to feel the Chicago pride. Even when your baseball team isn't in the World Series, necessarily, you still have to feel that little twinge of pride for Chicago. At least we have that, " said a McCain supporter who identified herself as Britney.
John McCain's running mate, Gov. Sarah Palin, did not speak at Tuesday night's gathering, but her presence loomed large. Exit polls revealed that one in four people said Palin was a consideration when they voted. Of those, the majority went with Obama.
Still, Sarah Palin is a powerhouse in conservative circles and has indicated she would like to return to the national stage.
Sarah Palin was set to fly back to Alaska Tuesday, where she has two more years left in her first term as governor.
John McCain will rest up at his ranch in Sedona, Arizona before returning to the senate where he promises to work to unify the nation.