With the immunity conferred by her office now gone, Ms. Park, 65, faces prosecutors seeking to charge her with bribery, extortion and abuse of power in connection with allegations of conspiring with a confidante, her childhood friend Choi Soon-sil, to collect tens of millions of dollars in bribes from big businesses like Samsung.

By law, the country must elect a new president within 60 days. The acting president, Hwang Kyo-ahn, an ally of Ms. Park’s, will remain in office in the interim. The Trump administration is rushing a missile defense system to South Korea so that it can be in place before the election.

The last time a South Korean leader was removed from office under popular pressure was in 1960, when the police fired on crowds calling for President Syngman Rhee to step down. (Mr. Rhee, a dictator, fled into exile in Hawaii and died there.)

In a sign of how far South Korea’s young democracy has evolved, Ms. Park was removed without any violence, after large, peaceful protests in recent months demanding that she step down. In addition to the swell of popular anger, the legislature and the judiciary — two institutions that have been weaker than the presidency historically — were crucial to the outcome.

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A protest last month in Seoul, South Korea, demanding Ms. Park’s resignation. 

“This is a miracle, a new milestone in the strengthening and institutionalizing of democracy in South Korea,” said Kang Won-taek, a political scientist at Seoul National University.

When crowds took to the streets, they were not just seeking to remove a leader who had one year left in office. They were also rebelling against a political order that had held South Korea together for decades but is now fracturing under pressures both at home and abroad, analysts said.

Ms. Park’s father ruled South Korea from 1961 to 1979. He founded its economic growth model, which transformed the nation into an export powerhouse and allowed the emergence of family-controlled conglomerates known as chaebol that benefited from tax cuts, anti-labor policies and other benefits from the government.

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Ms. Park, top center, with her father, Park Chung-hee, left, and her mother, Yuk Young-soo, right, in an undated family photograph. 

Ms. Park was elected in 2012 with the support of older conservative South Koreans who revered her father for the country’s breakneck economic growth.

But the nexus of industry and political power gave rise to collusive ties, highlighted by the scandal that led to Ms. Park’s impeachment.

The scandal also swept up the de facto head of Samsung, Lee Jae-yong, who was indicted on charges of bribing Ms. Park and her confidante, Ms. Choi.

In the wake of the Park scandal, all political parties have vowed to curtail presidential power to pardon chaebol tycoons convicted of white-collar crimes. They also promised to stop chaebol chairmen from helping their children amass fortunes through dubious means, like forcing their companies to do exclusive business with the children’s businesses.

With the conservatives discredited — and no leading conservative candidate to succeed Ms. Park — the left could take power for the first time in a decade.

The dominant campaign issues will probably be North Korea’s nuclear weapons program and South Korea’s relations with the United States and China.

If the opposition takes power, it may try to revive its old “sunshine policy” of building ties with North Korea through aid and exchanges, an approach favored by China. That would complicate Washington’s efforts to isolate the North at a time other Asian nations like the Philippines are gravitating toward Beijing.

Moon Jae-in, the Democratic Party leader who is leading in opinion surveys, has said that a decade of applying sanctions on North Korea has failed to stop its nuclear weapons programs. He has said that sanctions are necessary, but that “their goal should be to draw North Korea back to the negotiating table.”

He believes that Ms. Park’s decision to allow the deployment of the American missile defense system — known as Terminal High Altitude Area Defense, or Thaad — has dragged the country into the dangerous and growing rivalry between Washington and Beijing; China has called the system a threat to its own security and taken steps to punish South Korea economically for accepting it.

Conservative South Koreans see the deployment of the antimissile system not only as a guard against the North but also as a symbolic reaffirmation of the all-important alliance with the United States. Mr. Moon’s party demands that the deployment, which began this week, be suspended immediately. If it takes power, it says it will review the deployment of the antimissile system to determine if it is in South Korea’s best interest.

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Equipment for an American missile defense system arrived at an air base in South Korea on Monday. If the opposition party takes power, it says it will review the deployment of the system to determine if it is in South Korea’s best interest. 

As South Korea has learned in painful fashion, it cannot always keep Washington and Beijing happy at the same time, as in the case of the country’s decision to deploy the American missile defense system.

Yet Ms. Park’s impeachment was also a pushback against “Cold War conservatives” like her father, who seized on Communist threats from North Korea to silence political opponents and hide their corruption, said Kim Dong-choon, a sociologist at Sungkonghoe University in Seoul.

Ms. Park’s father tortured and even executed dissidents, framing them with spying charges. Now, his daughter faces charges that her government blacklisted thousands of unfriendly artists and writers, branding them pro-North Korean, and denied them access to government support programs.

“Her removal means that the curtain is finally drawing on the authoritarian political and economic order that has dominated South Korea for decades,” said Ahn Byong-jin, rector of the Global Academy for Future Civilizations at Kyung Hee University in Seoul.

Analysts cautioned that political and economic change will come slowly.

As Mr. Moon put it recently: “We need a national cleanup. We need to liquidate the old system and build a new South Korea. Only then can we complete the revolution started by the people who rallied with candlelight.”