Clinton's trip fulfills one of North Korea's two demands -- a visit from a high-profile emissary. As former president and husband of the current secretary of state, there could be few people of higher profile, and Gore founded Current TV, where the two journalists worked.
North Korea's second demand -- an apology -- was fulfilled by Hillary Clinton just a few weeks ago.
"The young women themselves have, apparently, admitted that they probably did trespass, so they are deeply regretful and we are very sorry it's happened," the former first lady said in an interview with ABC News last month. "Our most important goal is to make sure they get home safe."
Hillary Clinton's words were a clear departure from the administration's early rhetoric, and she also acknowledged that the State Department changed its approach in trying to free the two journalists. In June, she told ABC News' George Stephanopoulos that the charges against Lee and Ling were "absolutely without merit or foundation."
One thing about Clinton's trip is clear: He would not have gone to North Korea unless he was certain he would be coming back with the two journalists.
Despite a few tensions in the meeting, both sides got what they wanted. For Kim Jong-Il, it was a chance to boast a visit from a high-profile U.S. leader and an opportunity to pose for pictures with Clinton, and for the U.S., the safe return of the two detained journalists.
Ling and Lee were detained by North Korea in March for illegally entering the country. At the time, they were working on a story about human trafficking for Current TV along the Chinese-North Korean border. The two admitted crossing the border illegally and apologized.
But in June, Ling and Lee were found guilty of "hostilities against the Korean nation and illegal entry" and sentenced to 12 years of hard labor by North Korea's highest Central Court.
Many feared that the two would be used as bargaining chips by North Korea, whose nuclear ambitions remain undeterred despite tougher sanctions and stern rhetoric.
The U.S. has repeatedly requested amnesty for the women, and the Obama administration considered for weeks whether to send a special envoy to the communist state. But the negotiation had been drifting while North Korea ran a string of nuclear and missile tests in defiance of United Nations resolutions.
Ling's sister, National Geographic contributor Lisa Ling, expressed her concern to ABC in an interview with "Good Morning America" in June.
"She has a recurring ulcer," Lisa Ling said. "And we know that she has been allowed to receive some medication. But we, we know that her doctor is very concerned. He has written a letter, appealing to the North Korean government to at least allow her to see a physician. And as we all know, ulcers are exacerbated by stress."
Lee's husband, Michael Saldate, left to take care of the couple's 4-year-old daughter, said he has told his daughter Hannah only that her mother is at work.
Earlier this summer, Lisa Ling told ABC News' Bob Woodruff that she dreamed of the moment of her sister's release.
"It's a scene that I've kind of replayed over and over in my head. I just hope it comes soon," an emotional Ling said.
Jessica Kim and ABC News' Huma Khan contributed to this article.