Ron Pollack will step down as head of Families USA after more than three decades. He says he wants to turn his attention to “economic justice” issues beyond health care. (Marvin Joseph/The Washington Post)

During a trip to Mississippi in the 1960s to work on civil rights issues, Ron Pollack visited a sharecropper’s shack in rural Sunflower County.

There was not a scrap of food in sight. A young boy lay on a blanket, his stomach distended from malnutrition and his skin covered with flies. “He had no energy even to swat them away,” Pollack recalled. “I thought, ‘How could this be happening in the United States?’ ”

The experience ignited a lifelong passion to help low-income Americans, first as an anti-hunger activist and then as a co-founder of Families USA. The organization, one of the most influential health-care advocacy groups in the country, pressed for decades for affordable and accessible health care for all Americans and played a pivotal role in the passage in 2010 of the Affordable Care Act.

After 33 years as its executive director, Pollack will announce Wednesday that he plans to step down next March.

But even at 72, he has “zero interest” in retiring. The Queens native plans to spend the next several years working on “distributive justice” issues beyond health care.

A copy of the Affordable Care Act, signed by President Obama and congressional leaders, is displayed in the office of Families USA. The group played a key advocacy role in the law’s passage. (Marvin Joseph/The Washington Post)

“I’m interested in economic justice, in fairness, in who has and who hasn’t,” he said.

Under his direction, Families USA became a major player in almost every big health-care battle of the past several decades. It was at the forefront of pushing for the creation of the Children’s Health Insurance Program in 1997 and in opposing changing Medicaid into a block-grant program.

Along the way, Pollack, a lawyer and liberal Democrat, became known for his ability to bring together people of differing political views and economic interests.

One “strange bedfellow” relationship involved Chip Kahn, a Republican congressional staffer who eventually became an insurance and hospital lobbyist. In the early 1990s, Kahn was one of the architects of the “Harry and Louise” commercials that helped sink President Bill Clinton’s health-care reform plan.

“I think Ron was extremely unhappy with us,” said Kahn, now president and chief executive of the Federation of American Hospitals, which represents for-profit hospitals.

Beginning in the early 2000s, however, the two men started working together on incremental steps to reduce the number of uninsured Americans. And in the years leading up to the Affordable Care Act, Pollack arranged dozens of “stakeholder” meetings involving insurers, hospitals, businesses, unions, pharmaceutical companies and consumers — an effort that helped prepare the ground for initial industry support for the approach that became President Obama’s signature domestic achievement.

“Ron is able to work with people of all stripes,” Kahn said. “He knows instinctively that if you tried to get it all, you were just going to be a voice in the wilderness, you were not gong to be successful.”

Chris Jennings, a Democratic health-policy strategist who was Clinton’s health-care aide and worked with Pollack throughout the years, described him as a “gifted guy” whose efforts have helped tens of millions of low-income Americans. Jennings noted that Pollack effectively combines data with stories about “real people” — Families USA has a bank of anecdotes about individuals who have had problems and successes in the health-care system — to drive home policy points.

Pollack says that while the Affordable Care Act “is not perfect, it is probably the biggest advance in social benefits since adoption of the Medicare and Medicaid programs in 1965.” He notes with pride that Obama inscribed a copy of the law, which is displayed at the organization’s office: “To Ron and Families USA — You made this happen!” Then-House Speaker Nancy Pelosi (D-Calif.) and the chairmen of the five committees involved in drafting the legislation wrote similar words of thanks.

Still, Pollack expresses disappointment that millions of Americans who are eligible for the program haven’t signed up, that the battle over the law might continue if a Republican is elected president and that 19 states have not expanded Medicaid. But he thinks that number will drop if a Democrat wins the White House.

He recalls his frustration as he sat listening to the Supreme Court’s 2012 decision to uphold the overall law — but leave its Medicaid expansion up to individual states. “I never thought we would lose that,” he said.

Walking out of the court that day to face reporters, he remembers feeling deflated. A staffer turned to him and said: “Would you please put a smile on your face? We won.”