(CNN) Ady Barkan, a prominent progressive activist who is dying of ALS, endorsed Joe Biden on Wednesday, saying, "He is everything Trump is not."
The endorsement from Barkan, who previously endorsed Sens. Bernie Sanders and Elizabeth Warren in the Democratic presidential primary, is the latest sign of some progressives rallying around the former vice president now he's secured the Democratic nomination.
"I supported Elizabeth Warren and Bernie Sanders in the primary because they gave me hope. I was inspired by their bold progressive vision. Joe Biden was not my pick, and when they dropped out I was devastated. Maybe you felt the same way, and that is exactly why I wanted to tell you why I am supporting him in this election and why I hope you will too," Barkan, who speaks through a computer, said in a video on NowThis. "I am endorsing Joe Biden for president because he is everything Trump is not: compassionate, intelligent and committed to the public interest."
"Under a Biden presidency, our progressive movement will be able to harness our new energy and power in pursuit of justice and equity rather than constantly trying to defend ourselves from the latest atrocity," added Barkan, a "Medicare for All" supporter.
Biden has worked extensively to court progressive voters since securing the Democratic nomination. His campaign and allies recently teamed up with progressive leaders on joint task forces to address climate change, health care, the economy, criminal justice and education.
Barkan also heavily promoted Biden's empathy in his endorsement.
"Joe Biden has suffered tremendous loss in his life, but he has turned that loss into purpose and he has used his personal tragedies as bridges to connect with the suffering and humanity of others," Barkan said. "We have witnessed the danger of a selfish president. What a relief it will be to live in a country with a compassionate president who understands what it means to be in fellowship with others in the face of difficulty, in the pursuit of happiness."
In an interview with CNN last October, Barkan, a lifelong advocate on economic justice issues, explained how he intends to turn his disease into a legacy of health care advocacy. He was diagnosed in 2016.
"It's exhausting and overwhelming," Barkan said, describing how difficult ALS has made even the simplest tasks. "For me, ALS has been a lesson in exactly how broken our health care system is and why it's so important to fix it."
During the primary, Barkan conducted interviews with several of the Democratic presidential candidates in his home state of California, but not with Biden, who recently sat for a remote conversation with Barkan from his home in Delaware.
During the extended conversation with Biden for NowThis, Barkan and the presumptive Democratic nominee discussed their differences on Medicare for All. Biden does not support it but rather has proposed building on the Affordable Care Act, passed during the Obama administration while he was vice president, and providing a "Medicare-like" option.
"Thank you for that commitment and that bold agenda," Barkan said to Biden. "It's no secret that I support Medicare for All."
"I don't," Biden cut in.
Barkan continued, "And then I endorsed Elizabeth Warren and Bernie Sanders in the primary ... but you won the nomination and I respect that, and I am fully committed to beating Donald Trump."
In the emotional conversation, which put Biden's signature empathy on full display, the two bonded over what they hope their legacies will be and why their children are their motivating factors in the work they do. Barkan asked Biden what he hopes his late son, Beau, would say about him.
Biden replied that he would hope Beau would say his father was totally "authentic."
" 'Whatever he says he'll do, he will try to do. He'll never mislead you. When he makes a mistake, he'll tell you he makes a mistake and take responsibility. And even if it's not popular, he will push things that he feels are a matter of principle related to our values.' I hope that's what he would say."
Biden added that at the end of the day, what matters to him is how his kids will remember him. "Will they be proud of me?" he asked.
Barkan responded, "That's why I do the work that I do -- to make sure that Willow and Carl are proud of me."