A hand-lettered placard, reading “McDonald’s: Stop Fooling Around, $15 and a union,” caught the spirit of the crowd of at least 3,000 protestors in Chicago for a march to a McDonald’s restaurant in the downtown Loop area connected to the Chicago Board of Trade. In 236 cities in the U.S. and roughly 100 more around the world from Sao Paulo to New Zealand and from Glasgow to Tokyo, according to protest spokespeople, fast food and other low-wage workers joined together to pressure employers like McDonald’s to raise their workers’ pay.

Organizers claimed that it was the largest protest by low-wage workers in U.S. history. And it may very well rank as one of the broadest global worker protests ever undertaken against multinational corporations—one reinforced by recent investigations and lawsuits in Europe against the company for violations of labor, health, safety, tax and other laws.

The decision by McDonald’s to raise workers’ pay to at least $1 over the local minimum wage offers some help for the 90,000 employees at the 1,500 American restaurants run by its corporate headquarters, but the relief is minimal and leaves out the far greater number of workers at the company’s franchise outlets.

On average, the raise for eligible workers will lift pay to $9.90 an hour by July, up from $9.01, and to about $10 an hour in 2016. It does not apply to 660,000 employees at 12,500 McDonald’s franchises.

The increase follows moves by other low-wage employers but is more limited. It covers 12 percent of the McDonald’s work force and costs an amount equal to about 2 percent of profits in 2014. The recent raise at Walmart, to at least $10 an hour, covered nearly 40 percent of workers at a cost of about 6 percent of Walmart’s 2014 profits.

Clearly, if the McDonald’s raise were a response to the competition for workers, it would be bigger. And it does not come close to meeting protesters’ demands for $15 an hour, though the movement to improve fast-food workers’ pay has helped to push McDonald’s to this point.

McDonald’s announced on Wednesday that it would raise wages and offer new benefits to 90,000 employees in the 1,500 outlets in the United States that it owns and operates, responding to competitive pressure from a tighter job market and to labor campaigns drawing public attention to its pay policies.

The decision, however, does not affect the 750,000 employees who work for the more than 3,100 franchisees that operate roughly 12,500 McDonald’s restaurants around the country.

The company will increase wages to at least $1 over the local legal minimum wage for workers in restaurants under corporate control to an average of $9.90 an hour by July 1. That average will increase to more than $10 in 2016.

Employees who have worked in company restaurants more than a year will also be eligible for paid time off, whether they work full or part time. An employee who works an average of 20 hours a week might accrue as much as 20 hours of paid time off a year, the company said.

ATLANTA — On a recent Friday, Kwanza Brooks, a $7.25-an-hour McDonald’s worker, climbed into a 14-person van to take a four-hour ride from Charlotte, N.C., to Atlanta.

As she and other workers headed south, Ms. Brooks, a short, fiery woman, swapped stories with her companions about unsafe conditions and unfair managers. Upon arriving, they joined more than 400 other people — including home care aides, Walmart workers, child care workers and adjunct professors — at the Ebenezer Baptist Church, where the Rev. Dr. Martin Luther King Jr. had been a pastor.

The gathering on March 21 was in part a strategy session to plan for the fast-food movement’s next big wave of protests, which is now scheduled for April 15. But the meeting was also seeking to be something far more ambitious. Through some strategic alchemy, the organizers hoped the gathering would turn the fast-food workers’ fight for a $15 hourly wage into a broad national movement of all low-wage workers that combined the spirit of Depression-era labor organizing with the uplifting power of Dr. King’s civil rights campaign