Luis Alvarez, an NYPD detective who suffered from cancer brought on by his time at Ground Zero — died Saturday, nearly three weeks after joining comedian Jon Stewart in a moving plea to Congress to replenish the fund for 9/11 victims.

The 53-year-old retired Bomb Squad officer was scheduled to start his 69th round of chemo the next day — but his doctors said his liver shut down and there was nothing more they could do.

His death was announced by his family on Facebook in a post that read, “We told him at the end that he had won this battle by the many lives he had touched by sharing his three year battle. He was at peace with that, surrounded by family.’’

He was not diagnosed with colorectal cancer until 2016, but doctors linked to the three months he spent at the destroyed World Trade Center.

Shortly after his appearance before the House Judiciary subcommittee, he entered hospice care. The frail first responder told the politicians, “This fund isn’t a ticket to paradise, it’s to provide our families with care.

“You all said you would never forget,’’ he said. “Well, I’m here to make sure that you don’t.”

Alvarez was born in Cuba and brought to Astoria as a child.

He joined the Marines out of high school in 1984, and entered the Police Academy in 1990. He retired from the NYPD in 2010, then worked as an explosives expert for the Transportation Security Administration until 2017, shortly after his diagnosis.

“He made me want to be a better person, said John Feal, who also worked at the ruins of the World Trade Center and today works as a 9/11 victims advocate. “I let him into my world, and I’m humbled that he let me be part of his life.”

Feal gave Alvarez’ NYPD badge to Senate Majority Leader Mitch McConnell in an attempt to draw his support for moving a bill that would do what Alvarez and Stewart want.

“That badge is sacred and Louie’s legacy is stamped to that badge,” Feal said. “Mitch McConnell now has a moral responsibility to honor Louie’s memory.”

Rep. Pete King was scheduled to visit Alvarez in the hospice on Sunday. “He was absolutely consumed with getting this bill passed for other people,” he said, adding that he is “99 percent confident it’s going to pass.”

He noted that Alvarez would point out that each day that passes means more people are getting reduced benefits.

“If anything good comes from a horrible, tragic death like this, if Lou becomes the face of 9/11 victims, that will hopefully move the bill,” King said. “He was an incredible guy. Right to the end, I never saw a guy with more guts or class.”

Alvarez’ name trended on Twitter Saturday morning as police organizations, elected officials and ordinary people praised him.

“NYPD Detective Lou Alvarez died at peace knowing his life made a difference to others and will save lives in the future,” tweeted Sen. Chuck Schumer.

Sen. Kirsten Gillibrand called him a “true American hero.”

Rep. Jerry Nadler, who was one of the Congress members who listened to Alvarez’ testimony, said he “epitomized bravery.”

Alvarez is survived by three sons, David, 29, Tyler, 19, and Benjamin, 16; his parents, two brothers and a sister.