The character of McCain, forged in part by his military service, "is the kind of character that civilizations from the beginning of our history have sought in their leaders," Thompson said.
After outlining McCain's service in the Vietnam War during which he was a prisoner of war for more than five years, Thompson said, "Being a POW doesn't qualify anyone to be president, but it does reveal character."
McCain, ready to accept the party's nomination, and his vice presidential candidate, Alaska Gov. Sarah Palin, would "take the federal government by the scruff of the neck and give it a good shaking," said Thompson, who also sought the GOP nomination.
He also took a swipe at Barack Obama, saying the Democratic presidential nominee was "history-making in that he's the most liberal, most inexperienced nominee to ever run for president."
Thompson called upon Republicans to stand with McCain.
"We salute his character and his courage, his spirit of independence and his drive for reform, his vision to bring security and peace in our time, and continued prosperity for America and all of our citizens," he said. "For our own good, our children's (good), let us celebrate that vision, celebrate that belief, that faith, so we can keep America the greatest country that the world has ever seen.