Prosecutors will question Jun Byung-hun, the senior presidential secretary for political affairs, on Monday as a suspect in a bribery case involving his two former aides, according to the Seoul prosecutors' office.
He offered to resign over the scandal Thursday.
Jun's two former aides have been arrested for allegedly pressuring a local home shopping channel to donate 300 million (US$274,000) to the Korea e-Sports Association in 2015.
Prosecutors will question Jun, then the association's honorary chairman, to find out whether he was involved in the case.
The cable channel, Lotte Homeshopping, is suspected of giving the money seeking Jun's influence for the renewal of its broadcasting license. Jun was a member of the parliamentary committee in charge of media policies.
Jun is the first high-profile official in the Moon Jae-in government to face a corruption probe. He has denied any wrongdoing.
Prosecutors are known to have secured statements from the home shopping channel's officials that they were considering his influence when they decided to donate.
Prosecutors also apparently have financial records of Jun's family with transactions made with vouchers issued by Lotte.
Prosecutors are said to be considering filing an arrest warrant for Jun after further investigation.