The 60-year-old conservative, elected in 2012, has retained his post as party leader. Shinzo Abe has proved to be a relatively long-lasting prime minister in a country where leaders often hold power for about a year.
Abe was re-elected Tuesday as head of the ruling Liberal Democratic Party (LDP) despite falling popularity over his efforts to expand the role of the military and the stuttering economy.
The ruling LDP named Abe president after no other lawmakers filed applications to run against him in an election that had been set for September 20. Candidates had to gain support from 20 other lawmakers in the party to run.
He told reporters afterward that he would push his ongoing economic revival plan, saying "Abenomics is still partway through."
But GDP figures showed the economy shrank 0.3 percent last quarter, underscoring how his efforts to reverse years of deflation and laggardly growth have stumbled.
"While creating a virtuous economic cycle, I will spread the feeling of recovery to every nook and cranny of the regions and throughout the country, completely escape deflation and create growth in a strong, future-oriented economy," Abe told a crowd of supporters before registering for the vote.
Protesters in Tokyo against Prime Minister Shinzo Abe's security bill that would allow troops to fight overseas. August 30, 2015.
Abe's policy team has pledged to refocus on the faltering economy after spending political capital in the past year pushing unpopular legislation that would let Japanese troops fight overseas for the first time since the end of World War II.
Critics argue that the new law could allow Japan's military to be pulled into foreign conflicts even if there was no direct threat to the country or its people.
The changes have set off protests by tens of thousands of people and even a hunger strike by a group of Tokyo university students.
But with other parties in disarray, the LDP and their coalition partner the Komei party hold a two-thirds majority in the lower house of parliament and can override the opposition on most legislation.
Abe's current three-year term as LDP president ends on September 30. His new term will run until September 30, 2018.
jar/kms (AP, AFP, Reuters)