Seoul Mayor Park Won-soon was found dead on Friday, hours after he was reported missing, police said.
A police search team found his body in the forested hills of Mount Bukak near his official residence, reports Yonhap News Agency.
He is presumed to have taken his own life but the police will launch a probe into the cause of death.
Park, 64, had reportedly faced a probe into allegations of sexual harassment against a former female secretary.
She filed a formal complaint with the police on Wednesday over unwanted “physical contact” and “inappropriate” messages from Park, according to sources.
“A complaint has been received by the Seoul Metropolitan Police Agency,” a police official said but declined to elaborate.
“(The body) did not show particular signs of homicide,” the official said.
Park’s daughter filed a police report on Thursday evening that he “had left home four to five hours ago” after leaving a message that sounded like a will and his phone was turned off.
Park left his residence in the central Seoul ward of Jongno on Thursday morning.
CCTV footage showed him arriving by taxi at Waryong Park in a hilly neighbourhood in Jongno, said the Yonhap News Agency report.
Shortly after receiving the report of him missing, police officers launched a massive search operation around the area involving hundreds of officers, drones and sniffer dogs.
Park, a member of the ruling Democratic Party, had served as mayor of Seoul since 2011 and he was regarded as a potential candidate to run for the 2022 presidential elections.
Also a human rights lawyer and civic activist, Park had two more years in office.
By law, Seo Jeong-hyup, first vice mayor for administrative affairs, will serve as acting mayor until the by-election slated for April 7, 2021.