With just days to go before polling, Koh Seung-Duk, a celebrity lawyer and former lawmaker, was clear favourite to become the capital city's next superintendent of schools -- a powerful post in education-obsessed South Korea.
But his chances took a battering at the weekend when his estranged 27-year-old daughter claimed in a Facebook posting that he "never partook in the education of his own children".
Candy Koh -- raised in the US by Koh's ex-wife who divorced him when Candy was 11 -- said she had "next to no memories" of her father behaving as a parent before or after the divorce.
"Despite the existence of a telephone and Internet, Koh never called me or my brother to ask how we were doing," she wrote.
Koh, 56, made his name in the South as a prodigy who passed several, highly-competitive state exams at an unusually young age.
He has for decades lectured young South Koreans on study skills and the importance of education.
"As a child he neither educated nor rarely even spoke to, I must inform the citizens of Seoul that he does not qualify for this position," his daughter said.
The Facebook posting sparked a backlash against Koh on South Korean Internet portals and social networks, and received extensive coverage in Monday's national dailies.
"Education chief election turning into the most sensational soap opera," the JoongAng Ilbo wrote in an editorial.
At a hastily-arranged press conference on Sunday, Koh said he would not be withdrawing his candidacy and said his daughter was taking part in a "political plot" organised by an election rival.
"I am truly sorry for my daughter. But I will fight against the political plot to bring me down," he said.