WASHINGTON — With little fanfare, the Obama administration has been pursuing an aggressive campaign to restore protections for workers that have been eroded by business activism, conservative governance and the evolution of the economy in recent decades.

In the last two months alone, the administration has introduced a series of regulatory changes. Among them: a rule that would make millions more Americans eligible for extra overtime pay, and guidelines suggesting that many employers are misclassifying workers as contractors and therefore depriving them of basic workplace protections. That is an issue central to the growth of so-called gig economy companies like Uber.

A little more than a week ago, a federal appeals panel affirmed an earlier regulation granting nearly two million previously exempted home care workers minimum wage and overtime protections. And on Thursday, President Obama’s appointees to the National Labor Relations Board pushed through an important ruling that makes it easier for employees of contractors and franchises to bargain collectively with the corporations that have sway over their operations.

“These moves constitute the most impressive and, in my view, laudable attempt to update labor and employment law in many decades,” said Benjamin I. Sachs, a professor at Harvard Law School and a former assistant general counsel for the Service Employees International Union. The goal, he said, is to “keep pace with changes in the structure of the labor market and the way work is organized.”