North Korea made the decision because the 85-year-old Newman had apologized for his alleged crimes during the Korean War and because of his age and medical condition, according to the North's official Korean Central News Agency.
U.S. Vice President Joe Biden, who is traveling in Seoul, welcomed the release and said Newman was in Beijing. Aside from an awkwardly worded alleged confession last month, Newman has yet to speak publicly since being taken off a plane Oct. 26 by North Korean authorities while preparing to leave the country after a 10-day tour.
State Department spokeswoman Marie Harf urged Pyongyang to pardon "as a humanitarian gesture" another American, Kenneth Bae, who has been held in the North for more than a year.
Members of a group of former South Korean guerrillas who fought behind enemy lines during the 1950-53 Korean War said in an interview last week with The Associated Press that Newman was their adviser. Some have expressed surprise that Newman would take the risk of visiting North Korea given his association with their group, which is still remembered with keen hatred in the North.
The televised statement read by Newman said he was apologizing for killing North Koreans during the war, attempting to meet surviving guerrilla fighters he had training during the conflict and reconnect them with their wartime colleagues living in South Korea, and criticizing the North during his recent trip.
Newman's comments haven't been independently confirmed. North Korea has a history of allegedly coercing statements from detainees.
Newman's political value had "expired" for North Korea, said Chang Yong Seok, a senior researcher at Seoul National University's Institute for Peace and Unification Studies. Newman's written apology and the TV broadcast were enough for Pyongyang to show outsiders that it has maintained its dignity - something the proud country views as paramount, said Chang.
Chang said that detaining Newman also hurt impoverished Pyongyang's efforts to encourage tourism. "Keeping a tourist who entered the country after state approval doesn't look good for a country that is trying to boost its tourism industry," Chang said.
Some of those former guerrillas of the Kuwol unit in Seoul remember Newman as a handsome, thin American lieutenant who got them rice, clothes and weapons during the later stages of the war but largely left the fighting to them.
Newman oversaw guerrilla actions and gave the fighters advice, but he wasn't involved in day-to-day operations, according to the former rank-and-file members and analysts. Newman was scheduled to visit South Korea to meet former Kuwol fighters following his North Korea trip.
After he was detained, Newman was visited at a Pyongyang hotel by the Swedish ambassador, his family said in a statement, and he appeared to be in good health, receiving his heart medicine and being checked by medical personnel. Sweden handles American citizens' interests in Pyongyang as the North and the United States have no formal diplomatic ties.
Jeffrey Newman has previously said that his father, an avid traveler and retired finance executive from California, had always wanted to return to the country where he fought during the Korean War.
Tension remains on the Korean Peninsula, though Pyongyang's rhetoric against the U.S. and South Korea has toned down in recent weeks compared with its torrent of springtime threats to launch nuclear wars.
Before Newman, North Korea detained at least six Americans since 2009; five of them have been either released or deported after prominent Americans like former Presidents Bill Clinton and Jimmy Carter travelled to Pyongyang.
The country has held for more than a year Bae, the sixth detainee. He is a Korean-American missionary and tour operator who the North accuses of subversion.
Associated Press writer Eun-Young Jeong and Josh Lederman in Seoul contributed to this report.
Follow Foster Klug on Twitter at www.twitter.com/APklug