His brother, Mark McDermott, confirmed the death, saying the former congressman "died at peace."

McDermott's career in public life spanned nearly half a century, beginning with his election to the Washington House of Representatives in 1970. He served one term there before winning a state Senate seat in 1974, and in 1988 he was elected to Congress from Washington's 7th Congressional District, a seat he held until his retirement in 2016.

Along the way, he ran for governor three times and lost each time. His closest bid came in 1980, when he defeated incumbent Democratic Gov. Dixy Lee Ray in the primary but lost the general election to Republican John Spellman, then King County executive.

In Congress, McDermott was an outspoken liberal who championed healthcare access long before it became a mainstream Democratic priority. During his time in the state Legislature, he helped develop Washington's Basic Health Plan, an early program providing subsidized health insurance to low-income residents and working families. In his first congressional term, he sponsored the AIDS Housing Opportunity Act, which provides federal funds to local governments to house low-income people living with AIDS. He backed the Affordable Care Act and later introduced the American Health Security Act of 2015, legislation that would have established comprehensive health coverage for all Americans.

"Jim was one of the first and most powerful voices fighting to fix our broken health care system in Congress," Sen. Patty Murray said in a statement Friday. "He was passionate and fearless — and left a tremendous legacy on WA state and its people."

Sen. Maria Cantwell described McDermott as "as big as it gets in Washington state politics."

McDermott's commitment to healthcare stemmed from his time as a medical student at Cook County Hospital in Chicago, where he witnessed what his brother described as "the worst of the worst of human pain." He later moved to Seattle in 1966 for a fellowship in child psychiatry at the University of Washington Medical Center, then joined the U.S. Navy and worked as a psychiatrist treating soldiers and sailors returning from Vietnam.

He became a national figure in 2002 when he traveled to Baghdad with two other Democratic members of Congress and questioned the Bush administration's claims that Iraq possessed weapons of mass destruction. In a televised interview from Iraq, McDermott warned that the president would mislead the country into war.

"The president of the United States will lie to the American people in order to get us into this war," he said at the time.

The remarks drew fierce criticism from Republicans and conservative commentators, who dubbed him "Baghdad Jim" — a nickname that followed him for the rest of his career. But the administration's claims about Iraq's weapons program were later proven false.

"Somebody had to say that stuff," McDermott said when he announced his retirement, crediting his staunchly liberal Seattle district with giving him "the power to do it."

Seattle Mayor Katie Wilson praised McDermott's legacy, citing his work securing funding for Sound Transit and helping win federal recognition and protection for the Wing Luke Museum.

"Over his decades of service to the people of Seattle, Jim McDermott was a lion in the fight for working people and for peace," Wilson said in a statement Friday.

McDermott was born in 1936 in Chicago and grew up in the suburb of Downers Grove, the oldest of five children in a working-class, devout Christian family. He was the first in his family to attend college. A summer in Ghana through a nonprofit program called Operation Crossroads Africa — a precursor to the Peace Corps — broadened his worldview, his daughter Katherine McDermott said.

"From that experience, it really opened up his world to become the person who championed the rights of poor people around the world," she said.

His legislative legacy extended beyond healthcare. He helped author the 2008 Fostering Connections to Success and Increasing Adoptions Act, which expanded federal support for children in foster care and encouraged adoption. He chaired the House Ethics Committee and served as a senior member of the Ways and Means Committee. In 2007, King Letsie III of Lesotho knighted him in recognition of his leadership on the African Growth and Opportunity Act of 2000, which lowered tariffs and helped spur apparel trade in Africa.

McDermott also drew notoriety for leaking audio of a 1996 phone call between then-House Speaker Newt Gingrich and other Republican leaders discussing how to handle an ethics investigation. Rep. John Boehner sued McDermott over the leak, and the Seattle Democrat ultimately paid him more than $1 million in damages under a court order.

After retiring, McDermott moved to a cottage in the tiny village of Civrac-en-Médoc in southwest France. He reflected on his decades-long quest for single-payer healthcare in a 2024 interview.

"I spent 16 years in the Washington state Legislature trying to get single-payer healthcare. Then I spent nearly 30 years in Congress trying to get single-payer. Then I came to France, and in three months, I had single-payer," he said. "Was that mind-blowing? You bet."

His retirement set off a competitive race to succeed him, won by state Sen. Pramila Jayapal, who became the first South Asian American woman elected to the U.S. House.

"Congressman McDermott was a true champion for justice and left behind a long legacy of accomplishment," Jayapal said Friday. "For me, his commitment to immigrant justice was unparalleled."

McDermott was married twice, to Virginia McDermott and Therese Hansen. Both marriages ended in divorce. He is survived by two children, James and Katherine McDermott, and three grandchildren.

In his final days, as his health failed, Mark McDermott visited his brother at Harborview. He recalled leaning in to tell him that Democrats had done well in the midterm elections.

"I said, 'Brother Jim, we crushed the Republicans in the election,'" Mark McDermott recalled. "And he wakes up, and his eyes kind of are focused for a moment, and then he says, 'We've got a lot of work to do.'"