Gov. Jerry Brown signed legislation Wednesday entitling most California workers to three paid sick days a year, a priority of Democrats and labor advocates for years.

The legislation affects about 40 percent of California’s workforce, about 6.5 million people who currently are not paid when they fall ill.

“Whether you’re a dishwasher in San Diego or a store clerk in Oakland, this bill frees you of having to choose between your family’s health and your job,” Brown said in a prepared statement. “Make no mistake, California is putting its workers first.”

California is the second state in the nation, after Connecticut, to enact a statewide sick leave guarantee, long a source of controversy in statehouses across the country.

In California, lawmakers have been trying for nearly a decade to pass a paid sick leave bill, after San Francisco voters passed a sick leave guarantee in 2006. Previous bills stalled in the midst of a recession.

California’s economic condition has improved in recent years, however, and the bill Brown signed Wednesday is the latest of several labor-related measures he and the Democratic-controlled Legislature have enacted. Last year, Brown signed legislation raising California’s minimum wage to $10 an hour by 2016.

“Today, California made history,” Art Pulaski, executive secretary-treasurer of the California Labor Federation, said in a prepared statement.

He said that Brown, by signing the bill, “reaffirmed our state’s role as a national leader in advancing the fundamental rights of working people.”

Brown’s signature was never in doubt.

Before the bill passed narrowly through the Legislature, Brown negotiated an amendment to the measure to exclude home health care workers over concerns about cost. Two major unions, the Service Employees International Union and American Federation of State, County and Municipal Employees, withdrew their support for the bill after it was amended, and many Democratic lawmakers were torn.

Sen. Holly Mitchell, D-Los Angeles, said on the night of the vote: “This is B.S.”

“I resent the fact that we are picking between two sets of workers, “ Mitchell said.

Proponents of Assembly Bill 1522, by Assemblyman Lorena Gonzalez, D-San Diego, said providing employees paid sick days reduces employee turnover and the spread of illness in the workplace, a benefit to business.

Business groups said small businesses may not have enough employees to fill in for sick workers, and they objected to noticing and other requirements in the law. The California Chamber of Commerce opposed the bill, as did the California State Council of the Society of Human Resources Management.

Michael Kalt, an attorney for the human resources management group, said the bill will eliminate flexibility for companies that compensate employees in different ways.

“It’s a bill that has ramifications for a large number of employers,” he said, and it is likely to reverberate in other states.

“Things that start in California often don’t stop in California,” he said. “There are so many other states that look to what California is doing.”

Former Assemblywoman Fiona Ma, D-San Francisco, who introduced unsuccessful paid sick leave bills while in the Legislature, said, “Back in 2008, obviously, we were in the worst recession, and we couldn’t pass any bill that cost one dollar.”

Now, Ma said, “the situation is changing,” and she called the bill Brown signed “one step forward” for the state’s labor force.

Brown, who is running for re-election, traveled to Los Angeles, the state’s largest media market, to sign the bill.

While California moves to guarantee paid sick leave, legislatures in some other states, including Wisconsin, have enacted laws prohibiting local governments from enacting paid sick leave policies.

According to a U.S. Bureau of Labor Statistics report last year, about 61 percent of the nation’s workforce had access to paid sick leave in 2012. About three-quarters of full-time workers had that benefit, while only about 23 percent of part-time workers did.