The BBC's Seoul correspondent, citing local media, said that officials were so taken aback by his feat that they asked him to demonstrate how he was able to jump over the 3-metre fence to verify his claim.
The audacious defection sparked alarm that the high security demilitarised zone (DMZ) that separates North from South had been successfully crossed. The 2.5-mile-wide, 155-mile-long strip is fortified by wire fences, minefields and armed sentry posts.
Few defectors take the dangerous option of trying to break through the zone, with most of the 33,000 who have fled North Korea since the 1990s opting for risky but more achievable routes through China, arriving in the South via a third country, normally Thailand.
The Donga Ilbo news site reported on Monday that the still unidentified man's athletic background may have influenced his bold decision to make a run for the fence.
Scaling the barrier was only one of the formidable challenges he faced as the area surrounding the actual border line is strewn with minefields. The clearance of an estimated 2 million mines began during a diplomatic détente in 2018 but is still far from complete.
His escape was more low key, however, than the heart-stopping dash of a North Korean soldier in November 2017, who sprinted through a hail of bullets fired by his colleagues to enter the democratic South through Panmunjom, a military-run village that sits on the border. He was badly injured but survived.
The unusual defection attempt of a South Korean fisheries official to the North via the sea border this September ended more tragically when the man was shot by troops who then set his body on fire fearing he was carrying the coronavirus.