He was one of the 136 Koreans killed when an undersea coal mine off Japan's southern coast collapsed and flooded in 1942.
He had been drafted, like so many other Koreans, to support Japan's war effort, toward the end of its 1910 to 1945 occupation of the Korean peninsula.
Forty-seven Japanese were also killed in the mine.
Decades after the disaster and now 89, Jeon is still looking for closure and hopes his father's remains will be returned.
"I cannot tell you how devastated I am. It was really heartbreaking because I lost my father just like that. I was telling (people), 'My father died. My father died.' I was so sad."
Since he took office last year, South Korea's President Yoon Suk-yeol has sought to settle historic issues with Japan and has already met with Tokyo's leader.
Those discussions raised the hopes of people, like Jeon, that their relatives' bodies could soon be recovered.
But any such attempt would be complicated and costly.
The Chosei mine extended at least 1km out to sea and nearly 40 meters underground.
Japan's labor ministry told Reuters the cost of an excavation would likely run into millions of U.S. dollars.
Campaigners argue it is a price worth paying to recognize the hardship and injustice that families endured.
They held a memorial for the victims in Japan's Ube earlier this month.
Yang Hyeon is the Chairman of the South Korean Bereaved Families' Association.
He's also a nephew of one of the victims.
"The collapse incident at the Chosei coal mine was not an accident, but a predicted man-made disaster. After the Pacific War broke out, the then-Japanese government pushed ahead with the Chosei mine operation to increase coal output to support the war, even though it was in violation of a ban on undersea mining."
According to South Korean government estimates, the remains of as many as 10,000 Koreans are still in Japan.
They died in forced labor, digging mines or building dams.
