"I think President Clinton's assessment was that [Kim's] - he's pretty healthy and in control," President Obama said in an interview that airs Sunday on CNN's State of the Union, "And that's important to know, because we don't have a lot of interaction with the North Koreans. And, you know, President Clinton had a chance to see him close up and have conversations with him.
"I won't go into any more details than that. But there's no doubt that this is somebody who, you know, I think for a while people thought was slipping away. He's reasserted himself. It does appear that he's concerned about - he was more concerned about succession when he was - succession when he was sick, maybe less so now that he's well."
Obama also told CNN Chief National Correspondent John King that his administration's approach to the largely-isolated Asian nation "is a success story so far."
"[W]e have been able to hold together a coalition that includes the Chinese and the Russians to really apply some of the toughest sanctions we've seen, and it's having an impact," the president said.
The president added that he hoped to see progress toward more responsible behavior from North Korea's leaders.