DUBLIN, Ireland -- Finance Minister Brian Cowen was elected Ireland's new prime minister Wednesday, and he pledged to keep the country on its pro-European course through choppy economic waters.

A downcast-looking Ahern and lawmakers from all parties offered Cowen a standing ovation. Outside parliament, Cowen was mobbed by cheering, singing well-wishers as police escorted him to his prime ministerial Mercedes.

Cowen, 48, immediately reshuffled the Cabinet, appointing new ministers of finance, justice, foreign affairs and several other posts.

During his acceptance speech, Cowen's voice quivered with emotion as he noted that his political career began amid tragedy in 1984 when his lawmaker father, Ber, died of a heart attack. His wife, mother, two brothers and two daughters were watching from the public gallery above.

"I accept the honor with a genuine sense of humility. That sense is engendered in large part by my love for Ireland. This is a wonderful country. We are a fortunate people," Cowen said.

He said his top priority in coming weeks was to lead a successful referendum campaign to secure voter support for the European Union's next treaty. Ireland is the only EU member subjecting the Treaty of Lisbon to a popular vote -- and an Irish rejection June 12 could delay or block the painstakingly negotiated treaty.

A "yes" vote on the treaty would "secure our place in the heart of Europe," he said, while rejection would "only weaken our position and influence."

Cowen's rise comes at a time of growing economic problems in Ireland, which has thrived as a favored base for more than 600 U.S. high-tech multinationals. Unemployment this year has risen to 5.6 percent, a decade high, and government tax coffers dependent on Ireland's long-booming housing market have fallen sharply into the red because of the sudden downturn.