John M. Newmann, 70, an economist who spent much of his life battling kidney disease, which he parlayed into a prominent career as a patient advocate, health consultant and educator, died Aug. 12 at a daughter’s home in Berkeley, Calif.

Sara Newmann said her father had congestive heart failure. He had lived in Reston for more than 20 years before moving to an assisted living facility in Oakland, Calif., two years ago.

Dr. Newmann began his career as an international economist with the Ford Foundation. He had spent four years in Jakarta, Indonesia, when his kidneys failed in 1971 as a result of a congenital condition.

For years, he underwent dialysis treatments three times a week from a machine he kept in his home. At the same time, he attended graduate school and continued his work with the Ford Foundation in New York, where he funded scientific projects and examined human rights issues.

He gradually began to focus more of his attention on educating patients, legislators and the general public about kidney disease and organ transplants.

In 1980, Dr. Newmann founded a consulting company, Health Policy Research & Analysis, that conducted surveys and economic analyses for hospitals, government agencies and private corporations. Much of his work revolved around providing information about kidney disease and organ transplants.

“John epitomized the reality that productive life may continue after the onset of kidney failure,” Eli A. Friedman, a nephrologist at the State University of New York’s Downstate Medical Center in Brooklyn, said in a statement.

From 1981 to 1984, Dr. Newmann was president of the American Association of Kidney Patients. He testified before Congress, appeared on ABC’s “Nightline” and NBC’s “Today” show, and often spoke around the country about his personal history. He advocated for greater research into renal disease and encouraged patients to minimize the effects of kidney disease by paying attention to exercise, nutrition and medical treatment.

He received a kidney transplant from a cadaver in 1987, but when his body rejected the new kidney after two years, he went back on dialysis.

In 1993, he received a second kidney transplant from his daughter Emily, and he maintained normal renal functioning until his death.

“He was a very courageous man,” J. Michael Lazarus, his former personal physician and a dialysis expert who worked at Harvard, said in an interview. “The early survival average was two to five years. He lived much longer than the average lifespan. He was an unusual survivor.”

John Michael Newmann was born July 11, 1941, in Highland Park, Ill. He graduated from Amherst College in Massachusetts and received a doctorate in international economics in 1974 from Tufts University’s Fletcher School of Law and Diplomacy in Medford, Mass. He received a master’s degree in public health from Harvard University in 1980.

He was a co-founder of a cookie business in Boston in the early 1980s, which was eventually sold. He was also a consultant to the Urban Institute and, in 1989 and 1990, executive director of a Philadelphia-based nonprofit agency that assisted in providing organs for transplants.

He was a member of many national organizations and foundations dedicated to kidney disease and organ transplantation.

His marriages to Mary Misch and Lisa Aronson ended in divorce.

Survivors include two daughters from his first marriage, Sara Newmann of Berkeley and Emily Newmann of Cambridge, Mass.; two brothers; and two granddaughters.

As a child, Dr. Newmann was a musical prodigy on jazz piano and drums. He was 11 when he was introduced to trumpeter Louis Armstrong at a Chicago jazz club and two years later sat in on piano during one of Armstrong’s concerts.

They cultivated a close friendship, and Armstrong later visited Dr. Newmann at a children’s camp where he was a counselor — on the condition that no parents be allowed to attend his performance. Dr. Newmann eventually became an early organizer and supporter of the Louis Armstrong House Museum in New York.