Former President George W. Bush appeared on "The Tonight Show with Jay Leno" Tuesday night.

Former President George W. Bush said history will judge the decisions he made in the White House — yet it could take a while, maybe a couple of hundred years.

But Bush, who appeared on NBC’s “Tonight Show” Tuesday, said he doesn’t worry too much about it.

“You have to believe in what you’re doing, first and foremost,” Bush said. “I relied upon my faith, my family helped a lot and I had a good team around me and did the best I could do.”

“I’m also very comfortable with the fact that it’s going to take a while for history to judge whether the decisions I made are consequential or not. And therefore I’m not too worried about it," he said.

Bush noted that historians are still writing biographies about the first president, George Washington.

“My attitude, if they’re still writing biographies of the first guy, the 43rd guy doesn’t need to worry about it," Bush said.

Bush has mostly kept a low profile since leaving office in January 2009 with poor approval ratings as the economy struggled and the country was in the midst of two wars, Recent polling suggests some Americans have softened their opinion of him. Still, Bush has avoided inserting himself into public policy debates:

"I don't think it's good for the country to have a former president criticize his successor," he told Leno.

The former president, 67, was upbeat as he appeared with wife Laura Bush, the former first lady.

Bush was asked about his recent "heart scare," which surfaced in October when it was discovered by doctors in Dallas that he had a blocked artery. A stent, a metal device that holds open the vessel, was placed in the artery to restore blood flow and help prevent a heart attack.

“It was scary. It was very scary,” said Laura Bush. “I wasn’t that scared,” said Bush. Leno countered with, “You had Obamacare?” to laughs from the studio audience.

Bush this year dedicated his presidential library, which is on the Southern Methodist University campus in Texas. Part of it is a policy institute that promotes free enterprise and honors veterans. A museum with an exhibition is the cornerstone, he said.

"It's really important to remind our country that evil does exist, and the human condition elsewhere matters to our national security," Bush said. "We've got a policy institute where we promote free enterprise and freedom itself."

Bush also joked with Leno about his newfound hobby of painting.

"Is that second on your credits, president of the United States, painter, on your resume?" Leno asked.

"It depends on whether you like the paintings or not," Bush said to laughter.

The former first couple also talked about a global health initiative they've started at SMU, which is working on cancer in Africa.

"The sad thing is, if you're a woman, you're likely to have cervical cancer, and not much was being done about it," Bush said.

"So the Bush Institute, along with some partners, decided to do something about it. And so we do go to Africa. We work with the governments there. But we also like to spend time refurbishing clinics," he said.

This was the fourth time that Bush has been a guest on Leno's show since his first appearance during the 2000 campaign season.