The 34-year-old South Korean man, identified only by his surname Suh, was returned from the DPRK to South Korea via the border village at 11 a.m. local time (0200 GMT), Seoul's unification ministry said in a statement.
The DPRK's Red Cross informed South Korea Monday of its plan to repatriate Suh, who was caught on July 22 after illegally entering the DPRK. The South Korean side replied Monday afternoon to accept the repatriation.
The unification ministry said South Korea positively assessed the DPRK's return of a South Korean citizen from the humanitarian perspective.
Suh was reportedly under investigation over how and why he had illegally entered the DPRK.
The repatriation came amid the improving inter-Korean relations after South Korean President Moon Jae-in and top DPRK leader Kim Jong Un held their first summit meeting in Panmunjom on April 27.
Moon and Kim confirmed their joint goal of achieving a nuclear-free Korean Peninsula via complete denuclearization, agreeing to stop all hostile acts to defuse military tensions on the peninsula.