At the September election, English sought to extend a nine-year hold on power for his party. On election night, he appeared triumphant after the National Party won the most votes of any single party.

But the celebrations were short-lived. The liberal Labour Party was able to forge an alliance with two smaller parties and form a government under Prime Minister Jacinda Ardern.

English served eight years as finance minister before taking the top job. National Party President Peter Goodfellow said his prowess had steered the country through the global financial crisis and allowed the government to quickly get its books back into surplus.

Joined Tuesday by his wife and three of his six children, English became tearful when talking about their sacrifices.

“Through all our time together as a family, we have lived with the demands of public service,” he said. “Your strength and tolerance has enabled my career. I now look forward to our new life together.”

Ardern praised her former rival.

“He has always stood for what he believes in,” she said in a statement. “He is a man of clear convictions who has always had a genuine concern for the well-being of New Zealanders, and gave a huge portion of his working life to serving on their behalf.”

English’s departure could trigger a scramble for the party’s leadership. Possible contenders include lawmakers Simon Bridges, Amy Adams, Steven Joyce and Judith Collins.