He secured 215 votes against Economic Security Minister Sanae Takaichi's 194 in a tight runoff. The win positions Ishiba to become Japan's next prime minister, potentially signaling shifts in the country's economic and security policies.
The closely watched race featured a diverse field of candidates, including former Environment Minister Shinjiro Koizumi, Chief Cabinet Secretary Yoshimasa Hayashi, Foreign Minister Yoko Kamikawa, Digital Minister Taro Kono, and former Health Minister Katsunobu Kato.
Ishiba's victory came after a dramatic turnaround, having trailed Takaichi by 27 votes in the initial nine-candidate contest.
Ishiba is set to select new LDP executives on Monday and form his Cabinet after an anticipated confirmation as prime minister during an extraordinary Diet session beginning Tuesday.
