The proposal, which requires City Council approval, comes a day after de Blasio announced a $100 million effort to help ensure that the city’s health care resources are used by the uninsured, including immigrants in the country illegally — a move that immediately set up a contrast with Republican leadership in Washington.

De Blasio appeared eager to billboard that contrast with both announcements, leading to speculation among political consultants in New York City that his larger aim leading up to his State of the City address Thursday is to thrust his name back into the national conversation as a leader of progressive Democratic principles.

De Blasio did nothing to alter that impression during a news conference in City Hall, in which he presented his paid time off plan as a link in the long history of workers’ rights initiatives going back to the New Deal. He said that he would travel the country “very soon” to encourage other cities and states to follow suit.

“I’m focused on New York City, but I know what we do here could have a huge impact on the rest of the country,” de Blasio said. “I’m going to go out and talk about the things we’re doing here and the impact that they can make. I’m going to push other leaders to take on these ideas. I’m certainly going to push my party to support these kind of ideas.”

From almost the moment he became mayor, de Blasio has looked to extend his political reach beyond New York City, though his efforts have not always succeeded.

Now in the second year of his second term, the mayor seems to be renewing those efforts in earnest. He revealed the health care plan in a national television interview on MSNBC; he announced the paid vacation plan, which city officials say could benefit about half a million workers, in The Washington Post.

While the promise on health care largely amounted to improving customer service for coverage that has existed for decades, the paid-vacation measure would be genuinely new. No state or city in the United States has such a requirement, according to City Hall, though Puerto Rico does guarantee paid time off.

The mayor presented a list of mostly European countries that he said require paid time off for workers.

“We’re the exception — and it’s a bad exception,” de Blasio said of the United States.

The bill, as described by City Hall officials who did not share its text, would largely mirror one introduced in 2014 by Councilman Jumaane Williams of Brooklyn. The approach is modeled on the city’s paid sick-leave law and would likely apply to the same pool of roughly 3.4 million working New Yorkers. Businesses with fewer than five employees would be exempt. Full- and part-time workers at larger businesses would earn vacation time during the year, up to 10 days.

“Time off — we often treat it as a luxury: it is not,” said Williams, a candidate for public advocate and frequent critic of de Blasio who appeared with him at the news conference. “You cannot lead a healthy life if you do not have time off.”

De Blasio said he hoped the new rules would be “voted on quickly, but phased in smartly.”

Using data from the census and the federal Bureau of Labor Statistics, the city estimated that the law would affect some 500,000 workers, mostly in hotels, retail, restaurants and big-box stores. Most white-collar workers already get some form of paid vacation, and unionized workers usually receive it as part of their contracts.

Freelancers and contract employees would not be covered by the new rules, the mayor said.

The effort to broaden his reach comes as de Blasio has struggled with some local issues such as repairing public housing and implementing MetroCard discounts for the poor.

“It’s a good thing to have a mayor who thinks big and broadly,” said Kenneth Sherrill, a professor emeritus of political science at Hunter College. “But he sometimes does not seem to be terribly concerned with implementation.”

The new regulations would be enforced by the city’s Department of Consumer Affairs, which would investigate complaints of noncompliance and potentially issue fines or penalties. City officials have not determined the size of the fines.

City Hall officials said they discussed the measure with economists but did not broach it with business leaders, who seemed skeptical of it.

“The New York business community got no heads-up on this ‘national first’ announcement, so apparently we are not the audience being addressed, although local entrepreneurs will certainly be the victims,” said Kathryn Wylde of the Partnership for New York City, an influential business group.

James Parrott, director of economic and fiscal policies at the Center for New York City Affairs at the New School, said that businesses that have already had to adjust to the state’s $15 minimum wage and the city’s paid sick-leave law might struggle to provide paid vacation, too.

“As labor costs have increased over the last five years, businesses may have increased efficiency by taking the low-hanging fruit,” Parrott said. “It’s a fair question of whether there are more ways to increase efficiency.”

The mayor did not consult with the Democrat-dominated City Council as he shaped his paid vacation plan, according to several people with knowledge of the discussions. Council members were not told until the morning.

But the measure did not appear likely to meet resistance at the council, where the speaker, Corey Johnson, has been an enthusiastic backer of progressive policies.

City Councilman Williams applauded the mayor for following his lead.

“I’m just glad that the mayor is a big proponent of this now,” he said in an interview. “And I’m even prouder that we have a speaker who is willing to engage in the conversation. So I think it is a good day.”