The stunning escape occurred Monday at a jointly controlled area that is the only point where soldiers from the two sides face each other in the Demilitarized Zone.
Separately, Suh Wook, a senior JCS official, told lawmakers that Seoul's military believes four North Korean soldiers fired about 40 shots toward the defector, who appeared to have been hit at least five times.
On Tuesday, government and military officials had said the soldier was in critical condition, following gunshot-induced trauma to his inner organs, but doctors expected him to live.
While on average more than 1,000 North Koreans defect to South Korea every year, most travel via China and it is unusual for a North Korean to cross the land border dividing the two Koreas, which have been in a technical state of war since their 1950-53 conflict ended in a truce, not a peace treaty.
"There will need to be some questioning on why he defected after his treatment is over", ministry spokesman Baik Tae-hyun told a regular briefing.
Song would be the first ministerial-level Chinese official to visit North Korea since October 2015 when Politburo Standing Committee member Liu Yunshan visited Pyongyang and met with Kim.
North Korean military personnel are reportedly preparing for their winter training exercises as three U.S. aircraft carriers lurk near the Korean Peninsula in an unprecedented show of force by Washington's navy. "The individual initially took cover near a building on the southern side of the JSA."U.S. and South Korean forces recovered him at about 4 p.m., then took him to Ajou University Medical Center south of Seoul, along with a UNC security escort and translator, it said".
It's unclear what the soldier's conditions are or why he made a decision to defect to the South.
Panmunjomis where an armistice was signed to pause the Korean War.
They have previously accused South Korea of kidnapping or enticing North Koreans to defect.
The 1984 exchange of gunfire happened after North Korean soldiers crossed the border and fired, according to the U.N. Command.
The United Nations Command, which is run by the United States military and oversees the Joint Security Area, said that it was investigating the incident. In 1998, a North Korean solider fled to South Korea via Panmunjom.
Areas around Panmunjom were the site of bloodshed and defection attempts by North Koreans in the past, but there have been no such incidents in recent years.
The announcement about the Chinese envoy's visit came after Trump during talks with Xi last week urged him to to do more to use China's influence to pressure North Korean dictator Kim Jong-un to give up nuclear weapons programme.