Sasaki, who was the creative director of the opening and closing ceremonies at this year’s Games, said he told a planning group through a group chat that Naomi Watanabe could play a role as “Olympig”.
“There was very inappropriate expression in my ideas and comments,” Sasaki said in a statement released by Games organizers in the early hours of Thursday. “I sincerely apologize to her and to people who have been uncomfortable with such content.”
Hashimoto and Tokyo 2020 CEO Toshiro Muto plan to raise the issue at a press conference on Thursday, organizers said.
Sasaki’s resignation came soon after weekly magazine Shukan Bunshun reported his comments on Wednesday.
Mori, 83, a former prime minister, has been replaced by athlete-turned-politician Hashimoto, who has pledged to make gender equality a top priority at the Games.
The Olympic Games are scheduled from July 23 to August 8 and the Paralympics from August 24 to September 5.