"As of today, I will resign from the president's position," Mori said during an executive board and council meeting. "My inappropriate comments have caused a lot of chaos."
Mori, an 83-year-old former prime minister of Japan, sparked outrage last week after he made the remarks during an executive board meeting that was held online. When giving his "private opinion" about the Japanese Olympic Committee's goal of increasing the number of female board directors from 20% to more than 40%, Mori expressed concern about how that would affect the length of meetings, according to a report by The Asahi Shimbun, one of Japan's largest daily newspapers.
"A meeting of an executive board that includes many women would take time," Mori was quoted as saying by the newspaper. "Women are competitive. When someone raises his or her hand and speaks, they probably think they should speak too. That is why they all end up making comments."
He also referred to the Tokyo Olympics organizing committee, saying it "includes about seven women, but they all know how to behave," the newspaper reported.
Mori apologized for his remarks at a hastily-prepared press conference the following day. But by then, calls for his resignation were already trending on social media.
After announcing his resignation on Friday, Mori repeatedly said that he had regret over the remarks, but also said he had "no intention of neglecting women."
"The important thing is to have the Tokyo Olympics open in July," he added. "In order to make the games a success, I cannot be an obstacle to the preparations."
Mori was appointed to the position in 2014, just months after Tokyo won its bid to host the Olympics.
Early reports said that Mori had picked Saburo Kawabuchi, the 84-year-old former president of the governing body of Japanese soccer and an ex-player himself, to succeed him. Kawabuchi indicated on Thursday that he had been contacted by Mori and would accept the position if offered, according to a report by Japanese public broadcaster NHK. But the news sparked further outrage that the process of choosing Mori's successor was not transparent and that replacing him with another man who is even older would not help the situation.
During a press conference Friday night, Toshiro Muto, chief executive officer of the Tokyo Olympics organizing committee, said there has been "no concrete discussion" about Kawabuchi succeeding Mori. However, Muto divulged that Kawabuchi said he would turn down the job.
"We will pick a successor as soon as possible," Muto told reporters. "We need to ensure that the process to appoint a successor will be transparent, as established by the executive board."
Muto called Mori's remarks about women "extremely inappropriate" but noted his "significant contributions" to the preparation for the upcoming Games.
"Many things were possible because of him. That is a fact," he said.
Japan's chief cabinet secretary, Katsunobu Kato, has also emphasized the need for transparency in the search for Mori's successor.
"Matters concerning personnel and operations must be transparent," Kato said at a press conference Friday morning.
Following Friday night's press conference, the Tokyo Olympics organizing committee released a statement addressing "concern" over Mori resigning just months before the Games are slated to open. The committee asked for the public's "continued cooperation" and vowed to do its "utmost to re-earn your trust."
"We ensure you that we will proceed with the appointment of a successor in a swift and transparent manner in order to limit the impact on our preparation for the Games," the committee said. "We will also consider specific actions to take, in light of opinions and recommendations voiced at today's gathering, regarding how we can use this opportunity to further promote gender equality in society."
The controversy came just as Olympics organizers unveiled a series of "playbooks" for how they plan to hold a safe and successful Games in Tokyo this summer amid the coronavirus pandemic.
The 2020 Summer Olympics were supposed to kick off in the Japanese capital last year on July 24, but in late March, amid mounting calls to delay or cancel the upcoming Games, the International Olympic Committee and Japanese organizers announced that the event would be held a year later due to the COVID-19 pandemic. They have been outwardly staunch in their determination to go forward with the Games ever since, despite the fact that Japan -- and much of the world -- has seen a rise in coronavirus infections in recent weeks.
With just over five months left until opening day, Japan's mass vaccination program has yet to begin and Tokyo remains under a state of emergency due to a climbing number of COVID-19 cases and a growing death toll. Moreover, a recent poll by Japanese news agency Kyodo found that around 80% of people in Japan believe the Tokyo Olympics should not be held this summer.
"There shall be no delay," Muto told reporters Friday.
ABC News' Rosa Sanchez contributed to this report.