Jack Schlossberg, the grandson of the late President John F. Kennedy, has spoken candidly about the profound impact of his older sister Tatiana's death, describing her as his "best friend." Tatiana Schlossberg, 35, passed away in December 2025 after a battle with acute myeloid leukemia, an aggressive form of blood cancer. In a new interview with Vanity Fair, Jack, 33, who is running for Congress in New York's 12th District, confessed that he doubts he will ever fully "process" his grief.
A Bond Like No Other
"The world will never be the same for me, not only since she passed away, but since she was diagnosed with cancer about two years ago," Jack said. "She was my best friend. We could finish each other's sentences. And no one loved me or was a bigger fan of me than my sister." He added that he misses her constantly and thinks about her every day. However, her memory has become a driving force in his life. "It really does motivate me to do everything I can with every waking moment I have, because I realize it could have just as easily been me," he explained. "I have an obligation to her, not just to myself, to make the most out of my precious life and all that I've been given to give back to others and ensure we can fund cures for the type of cancer that took her life, and for other cancers."
A Call to Public Service
Jack emphasized that his sister's death has made him "all the more motivated, engaged, and focused on making the most out of my life." He believes there is "no higher calling than public service" and views politics as a noble profession. "She wanted me to win, and I intend to honor her by doing just that," he stated. Tatiana's death was announced by the JFK Library Foundation in December. She had revealed her cancer diagnosis in a New Yorker essay published on November 22, 2025, the 62nd anniversary of her grandfather's assassination. She was diagnosed in May 2024, shortly after the birth of her second child, Josephine, with her husband George Moran. The couple also have a three-year-old son, Edwin.
Her Battle with Cancer
Tatiana underwent initial rounds of chemotherapy before receiving a stem cell transplant from her older sister, Rose Schlossberg, who was a match. The transplant initially put her into remission, but the cancer returned. She tried various treatments, but in her essay, she wrote that her doctor told her he could keep her alive for "a year, maybe." In a March interview on CBS Sunday Morning, Jack recalled his final conversation with Tatiana about his congressional run. "The last thing that she said to me was, 'You better win,'" he shared.
