Carl Kohsuke Watanabe M.D.

Carl Kohsuke Watanabe, M.D., passed away peacefully at home in San Francisco on December 3, 2025, at the age of 95. He was born on July 8, 1930, in Sacramento, California, to Genzo and Eki Watanabe.
In 1939, the family moved to his father’s hometown of Mifune in Kumamoto Prefecture, Japan, where they remained through the end of World War II. After returning to California in 1949, Carl joined the U.S. Army and was assigned to the Military Intelligence Service during the Korean War. There, he studied the Korean language and served as an interpreter while stationed in Japan. He maintained lifelong friendships with his fellow veterans.
Following his military service, Carl enrolled at San Mateo Junior College and later graduated from the University of California, Berkeley, with a degree in Biology. He went on to attend Washington University in St. Louis, where he earned his Doctor of Medicine degree. During this time, he married Sumiko Ishibashi, a native of Tokyo.
After medical school, Carl completed his internship and residency in Internal Medicine at Highland Hospital in Oakland. He subsequently established a private practice in Berkeley, affiliated with Alta Bates Medical Center, where he served the East Bay community with dedication and compassion until his retirement in 2010, at the age of 80.
Carl greatly enjoyed traveling with his family, especially to Japan, and held fond memories of skiing and fishing during family vacations to Lake Tahoe. Always energetic and eager to explore new places, he delighted family and friends with stories from his past and was known for his boundless enthusiasm. A lifelong learner, Carl remained intellectually curious throughout his life and, even in his final days, kept a long list of medical articles to read alongside works of Japanese literature. Most of all, he cherished time spent with his grandchildren.
Carl was preceded in death by his beloved wife, Sumiko. He is survived by his sister, Hideko Winans of Berkeley; his brother, Edward Watanabe of Williamsburg, Virginia; his son, Andrew Watanabe (Mihoko) of Berkeley; his daughter, Aileen Watanabe (John Hadeler) of San Francisco; his grandchildren, Coco and Noe Watanabe and William and Edward Hadeler (Sarah); and his great-grandson, Lane Hadeler.

To plant a tree in memory of Carl Kohsuke Watanabe M.D., please visit our Tribute Store.