President-elect Joseph R. Biden Jr.’s ability to reshape the economy through legislation hinges in large part on the outcome of the two Georgia runoffs in January that will decide control of the Senate. But even without a cooperative Congress, his administration will be able to act on its agenda of raising workers’ standard of living and creating good jobs by taking a series of unilateral actions under existing law.

“If you pay attention to what Trump did and go about it from a different viewpoint, you can accomplish a lot,” said Thomas M. Conway, the president of the United Steelworkers union.

Much of this work will fall to the incoming labor secretary, whose department has the authority to issue regulations and initiate enforcement actions that could affect millions of workers and billions of dollars in income.

Mr. Biden’s labor secretary could substantially expand eligibility for time-and-a-half overtime pay. In 2016, the Obama administration extended that eligibility to salaried workers making less than about $47,500 a year, but a federal court suspended the Obama rule, and President Trump’s Labor Department set the cutoff at roughly $35,500 rather than continue to appeal. The Biden administration could make millions more salaried workers eligible for time-and-a-half overtime pay by reviving or expanding the Obama criterion and defending it in court.

The Labor Department will also have an opportunity to fill several monitoring and enforcement positions created under the United States-Mexico-Canada Agreement that are likely to go unfilled during the Trump administration. The accord, a revision of the North American Free Trade Agreement, allows the United States to block imports from facilities in Mexico that curtail workers’ rights to unionize and bargain collectively. Pursued aggressively, the enforcement could help mitigate downward pressure on U.S. manufacturing wages stemming from unfair competition with Mexico.

Mr. Biden’s Labor Department is likely to be more assertive in a variety of other enforcement efforts than its predecessor, which ended an Obama-era policy of typically trying to collect double the amount of wages that lawbreaking employers failed to pay workers under minimum-wage or overtime requirements.

“Just getting back wages in small amounts doesn’t provide any incentives for companies to comply,” said Catherine Ruckelshaus, general counsel of the National Employment Law Project, which has ties to the Biden transition team. The Biden administration is likely to revive the Obama approach.

Revisiting Labor Rules

Union membership, which has dropped to 10 percent of U.S. workers from roughly double that figure in the early 1980s, could receive a significant boost during the Biden administration, which has signaled that it intends to work closely with the labor movement.

Under Mr. Biden, the National Labor Relations Board is likely to be far more aggressive in punishing employers that appear to break the law while fighting union campaigns. It can issue a regulation making it easier for the employees of contractors and franchises to hold parent companies accountable for violations of their labor rights, such as firing workers who try to unionize.

According to Benjamin I. Sachs, a Harvard Law School professor, the board could also seize on a legal provision that allows the federal government to cede jurisdiction to the states for regulating labor in certain industries. That could enable a state like California or Washington to create an arrangement in which gig workers, with the help of a union, negotiate with companies over wages and benefits on an industrywide basis in that state, a process known as sectoral bargaining.

Under such a system, a union would have to show support from a fraction of workers in the industry, such as 15 or 20 percent, to be able to negotiate with multiple gig companies on behalf of all workers. By contrast, under federal law, the union would typically have to win majority support among the workers it sought to represent, a daunting challenge in a high-turnover industry like gig work.

Other labor experts, like Wilma B. Liebman, who led the labor board in the Obama administration, affirm that the board can cede its authority to states but are more skeptical that it would do so in the case of gig workers.

Helping Home-Care Workers

The federal government, through its control of the Medicaid program, could accomplish something similar for home-care workers, who usually work independently or for small agencies that have little power to raise pay because states set the rates for their services. The agencies sometimes resist union campaigns aggressively for fear that allowing workers to bargain for higher wages will put them at a competitive disadvantage.

A handful of Democratic-leaning states, like Washington, have addressed this issue by allowing workers to bargain with the state for rate increases that effectively apply industrywide, eliminating the downside that a single agency would face if it raised wages unilaterally.

The Service Employees International Union, which represents home-care workers across the country, believes that the Biden administration could encourage other states to create such industrywide bargaining arrangements — for example, by making additional money available to states that adopt this approach. Hundreds of thousands of additional home-care workers could benefit.

The federal government, under a provision in the Medicaid law that requires states to keep payments high enough to ensure an adequate supply of home-care workers, could also intervene directly to raise wages and benefits for these workers.

“We look forward to working with the Biden administration to make changes to the Medicaid program that can turn home-care jobs into good union jobs,” said Mary Kay Henry, the president of the service employees union.

Using Federal Contract Clout

Outside of specific agencies like the Labor Department, the Biden administration will have considerable leverage over the working conditions of the roughly five million workers employed by federal contractors and subcontractors.

President Barack Obama signed executive orders raising the minimum wage for these workers to $10.10 an hour and entitling them to at least seven days a year of paid sick leave. Mr. Biden could raise the minimum wage for contractors much further — some are urging $15 an hour — while also mandating that they receive paid family leave and paid vacation days, as proposed by Heidi Shierholz, a senior Labor Department official under Mr. Obama.

Mr. Biden could also use the federal government’s buying power to create more domestic manufacturing jobs, a goal he highlighted during the campaign. One approach would be to sign an executive order laying the groundwork for a Buy Clean program of the sort that California introduced in 2017.

Under the program, contractors bidding on state infrastructure projects, like steel makers and glassmakers, must adhere to a certain standard for so-called embodied emissions, essentially the amount of carbon emitted when the material is produced, transported and used in construction. Tighter limits tend to favor domestic manufacturers over competitors in countries, like China, that are farther away and where production is often less environmentally friendly.

“The incoming administration has broad power to put forth an idea like Buy Clean,” said Mike Williams, deputy director of the BlueGreen Alliance, a coalition of unions and environmental groups. That includes establishing a way to measure emissions and creating a database in which manufacturers are required to disclose them.

Promoting Job Creation

While existing law requires the federal government to favor domestic suppliers in procurement, a variety of waivers allow agencies to award contracts to overseas companies. Mr. Biden noted during the campaign that the Defense Department spent billions on foreign construction contracts in 2018, and he has pledged to close such loopholes.

The most aggressive version of this approach would be to revoke a broad waiver that allows agencies to treat purchases from dozens of countries with which the United States has trade relations — including Japan, Mexico and many in Europe — as though they were made in America. Mr. Biden has indicated that he is more likely to try to negotiate new rules with trading partners to address this issue.

The Biden administration could also instruct contracting officers to broaden the criteria they use to assess bids. A set of contracting rules laid out in a 1984 law, along with Washington’s growing preoccupation with spending cuts in recent decades, led administrations of both parties to focus on seeking the lowest upfront price.

But the Biden administration could elevate value over price — under the same logic that says a $30,000 Cadillac may be a better deal than a $25,000 Ford Focus. The approach would favor companies whose workers are better paid but also better trained and more productive than competitors’.

Mr. Biden could set some of these changes in motion through an executive order stating that federal agencies should focus more on quality and working conditions when assessing value. But because executing many of these shifts would be a question of day-to-day management rather than sweeping changes, some policy experts have proposed that the Biden White House create a dedicated office to oversee procurement across the administration.

Anastasia Christman, an expert on government contracting at the National Employment Law Project, compares the idea to the White House Office of Faith-Based and Community Initiatives that George W. Bush created in the early 2000s, whose goal was to scour the federal bureaucracy for ways that religious organizations could compete for government funds. In this case, Ms. Christman said, the objective would be to ensure that contracting officers across agencies are using the right criteria in awarding contracts.

“It would help contracting offices think differently about how to do the assessment,” Ms. Christman said. “How do you ask right kind of follow-up questions? Why is this bid lower than all others? What is that resting on?”