Ken Thompson, Brooklyn's first African-American district attorney, died Sunday, Oct. 9, at Memorial Sloan Kettering Hospital just days after revealing his cancer diagnosis, his family said. He was 50 years old.

"With a heavy heart, the family of Brooklyn District Attorney Ken Thompson announced that the District Attorney passed away today after a hard fought battle with cancer," Thompson's family said in a statement Sunday. He was surrounded by family at the time of his death.

Thompson announced just days earlier that he was temporarily stepping down from his position while receiving treatment for cancer, but did not say how long he had been battling the illness for.

“As Brooklyn District Attorney, I’ve dedicated myself and our Office’s resources over the past three years to keeping the people of our great borough safe while strengthening our commitment to reform and improve our criminal justice system,” Thompson had said in a statement. “And now I am prepared for another fight.”

Thompson had served as district attorney since 2014. He's survived by his wife Lu-Shawn, their two children, Kennedy and Kenny, his parents and his brother and sister.

Brooklyn Chief Assistant District Attorney Eric Gonzalez said in a statement that Thompson "was a giant among those seeking to reform the criminal justice system and we are all privileged to have worked under his transformative leadership these past three years."

"In that short period, he transformed the Office into a model urban prosecutor's office, with a mandate to do justice and treat everyone and every case fairly and with utmost integrity," Gonzalez said. "Among his many initiatives, he created a model for correcting wrongful convictions, instituted a marijuana policy that would later be replicated citywide and started a summons forgiveness program that would also be instituted in several other jurisdictions."

Gov. Andrew Cuomo said in a statement that he was "profoundly saddened" to hear of Thompson's death, and he directed all flags to fly half-staff on Monday.

"Ken was a dedicated public servant who embodied the highest principles of the law, and his grand presence will be sorely missed," Cuomo said, adding that Thompson was "an effective, aggressive civil rights leader – and a national voice for criminal justice reform."

Mayor Bill de Blasio and Chirlane McCray said in a statement, "With a life and promise cut far too short, our city was blessed with but a glimpse of Ken's unwavering commitment to justice and his unrivaled pursuit of a more fair system for all those he served. Our courtrooms and our communities have no doubt been dealt a blow with Ken's passing, but I am confident the indelible mark left by his public service will forever be a part of the fabric of our justice system. Tonight we mourn the loss of a champion of reform. Our task now will be to rise each day forward in the spirit Ken lived his life.”

Attorney General Eric T. Schneiderman said he was "devastated" to learn of the passing of his "dear friend," remembering Thompson as "a wonderful and committed public servant."

Brooklyn Borough President Eric Adams called Thompson "a true champion of justice" and said that the DA "set a gold standard for public service that has had a lasting impact across our country."

“Ken was more than my colleague; he was my friend," Adams said in a statement. "I am honored to be beside him in the storied history of Brooklyn as the first African-Americans to hold boroughwide office, and I know that many young men and women will reach a bit higher because of the heights that Ken reached in his career and his life."