Angela Merkel, Germany's chancellor and party leader of the Christian Democratic Union (CDU), waves to supporters during her final election rally in Berlin, Germany, on Saturday, Sept. 21, 2013. Merkel closed her campaign evoking the benefits of European unity as Social Democrat Peer Steinbrueck lambasted her as ineffectual and "backward-looking." (Krisztian Bocsi/Bloomberg)

German Chancellor Angela Merkel’s center-right Christian Democrats won a historic victory Sunday, with voters overwhelmingly endorsing the party with the largest margin since German reunification in 1990, according to near-final election projections by German television networks.

The results, which were closely watched worldwide because of Germany’s paramount economic leadership within Europe, were a ringing endorsement of Merkel’s stewardship over years of international crisis and recession that barely touched German soil. Merkel, who has led the country since 2005, said that she planned to stay for a full four-year term, putting her in the pantheon of long-serving German leaders Helmut Kohl, who united East and West Germany, and Konrad Adenauer, who rebuilt West Germany after World War II.

Merkel’s party appeared to be just short of an absolute majority of Parliament’s 598 seats, a rarity in German’s usual coalition system that has not happened since the time of Adenauer. Early Monday, projections by Germany’s public television networks with more than four-fifths of the vote counted were that Merkel would miss the mark by three or four seats and would be forced to seek a junior partner to govern. The likeliest candidate would be the center-left Social Democrats, analysts said. The party was the runner-up in Sunday’s elections and served in a coalition with Merkel from 2005 to 2009.

If the alliance is renewed, the ascent of the Social Democrats will probably make Germany more willing to support stimulus packages and be less rigid about austerity when dealing with troubled European partners such as Greece, Spain and Portugal. But any coalition deal could take weeks of haggling.

Merkel, normally reserved, appeared jubilant on Sunday in front of cheering supporters in Berlin, who chanted “Angie, Angie” and occasionally interrupted her speech.

“We will do everything in the coming four years to ensure that they are successful for Germany,” she told the crowd. “We are waiting for the final results . . . but we can already celebrate today, because we really did well. This is a fantastic result.”

Merkel’s Christian Democrats and the allied Bavarian Christian Social Party appeared to have won 41.7 percent of the vote, according to projections early Monday, the highest proportion since German reunification in 1990. The Social Democrats appeared to have captured 25.6 percent. The Greens and the Left Party also cleared the bar to enter Parliament.

But the earthquake of an election appeared to have displaced Merkel’s current coalition partners, the pro-business Free Democrats, who were kicked out of Parliament for the first time in modern Germany. The party captured only 4.7 percent in preliminary results, short of the 5 percent necessary to qualify for seats in Parliament and down from 14.6 percent four years ago.

The upstart anti-euro Alternative for Germany party, which was formed this year, was also shy of getting into Parliament, at 4.7 percent. Supporters who were camped out at a Berlin hotel appeared resigned to defeat late Sunday. Even so, the near miss was a sign of growing discontent about Germany’s role as the European lender of last resort. Had the party made it into Parliament, Germany would for the first time have had a major anti-European voice in domestic political discussions.

Merkel, 59, a popular but publicly reserved leader, has earned the respect of many Germans for her stewardship through Europe’s economic crisis, projecting steely resolve abroad on bailouts even while many outside critics said that Germany should be more generous to prevent a breakup of the 17-nation euro zone.

That breakup did not occur, and the worst of the danger appears to be over, even as Germany’s unemployment rate has dropped from more than 11 percent when Merkel first became chancellor in 2005 to 5.3 percent now.

Many challenges face Merkel over the next four years, including how to sustain growth as the population shrinks, how to restore prosperity across Europe and how to address the nagging feeling among many of Merkel’s critics that gaps between Germany’s rich and poor are widening. But she appears to have won the confidence of the public to tackle the issues.

Merkel’s chief rival, Peer Steinbrück, 66, a longtime Social Democratic politician from the northern city of Hamburg who served as finance minister under Merkel from 2005 to 2009, struggled to connect with voters. His preferred campaign technique — to take relatively unscripted questions at rallies — was a marked departure from Germany’s buttoned-up political playbook. But gaffes, including a stated desire to boost the chancellor’s pay to an avowal that he would never buy cheap wine, helped feed the perception that Steinbrück was not as much a man of the people as Social Democrats typically aspire to be.

“The ball is in Ms. Merkel’s court,” Steinbrück said in a subdued appearance at Social Democratic party headquarters Sunday night. “She must form a majority.” He ruled out serving as a minister under Merkel if the parties form a coalition.

Merkel impressed many Germans with her understated style. The daughter of a Protestant minister who trained as a chemist in communist East Germany, Merkel rose to prominence in the 1990s under Kohl.

“She’s doing a good job. If she was doing a bad job, she would have been voted out,” said Gabriele Grother, 54, the caretaker of a school in the tony Charlottenburg neighborhood of Berlin. Grother said that before Merkel took office in 2005, she could find only a few hours of work a week. But since Merkel has led Germany, “there’s been work.”

Petra Krischok contributed to this report.