Former defense minister Shigeru Ishiba has won his fifth bid to become the leader of Japan’s ruling party on Friday, lining him up to become the country’s next prime minister.

Ishiba defeated economic security minister Sanae Takaichi, who was vying to become Japan’s first female prime minister, in a runoff after the two won the most votes in the first round in a crowded field of nine candidates.

The 67-year-old veteran politician will succeed outgoing Prime Minister Fumio Kishida, who threw the Liberal Democratic Party for a loop when he announced in August that he would not be running for its top office, effectively ending his three-year term. 

Ishiba is now expected to be approved as prime minister in a vote by parliament on Oct. 1 due to the LDP having a majority in both chambers of the legislature, effectively ensuring its chief becomes the next prime minister.

The election outcome is set to have major implications for Japan, with Ishiba inheriting a party marked by a corruption scandal, an economy in a precarious transition from years of stagnation, and emerging security and diplomatic threats on the world stage.

In the run up to the election, Ishiba endorsed the Bank of Japan’s policy of steadily raising interest rates and voiced concerns about depreciation of the yen, differentiating himself from runoff opponent Takaichi who supported ultra-low-rates.

In March, the Bank of Japan exited a policy of long-held negative interest rates and then raised rates again in July. Ishiba had been a critic of the BOJ’s negative interest rates policies under former premier Shinzo Abe’s “Abenomics” policies.

Ishiba has also taken bold stances on foreign policy, calling for the establishment of an Asian NATO to deter increasing threats from China and North Korea.

The lawmaker will likely be closely watching the U.S. presidential election in November, which could have profound effects on Japan-U.S. relations.

Soon after Ishiba secured the leadership position, U.S. Ambassador to Japan Rahm Emanuel congratulated him on the victory.

“Looking forward to working with Japan’s new prime minister to strengthen the #USJapanAlliance and cultivate even closer ties,” he said in a social media post.

Ishiba’s victory ends a streak of four previously failed runs and appears to have come as a surprise to many. A local media report on Tuesday had suggested that some of his past actions and outspoken nature had made him unpopular among his peers.

Meanwhile, a hashtag “First woman prime minister,” had been trending on social media platform X in Japanese after Takaichi netted the most votes in the first round.

Takaichi, 63, was one of two women in the race and had argued that Japan’s economy needed more fiscal stimulus and to strengthen in fields including diplomacy and defense.

Polls had suggested that the favorites in the election had also included ex-environment minister Shinjiro Koizumi alongside Takaichi and Ishiba. However, the politician, who was vying to be Japan’s youngest ever prime minister, was unable to secure enough votes to advance to the next round.