Thomas Michael "Mike" Duffy, M.D., passed away peacefully surrounded by family on December 30, 2025, at the age of 82. Beloved husband of Rosemary Duffy (née Pribilia) for 56 years; loving father of Amy (Patrick) Murphy, Sue (Nate) Winter, Ann Duffy, and Jean (Nate) Paullin; proud Grandpa "Papa" of nine grandchildren and two great-grandchildren; and cherished brother of Bob, Steve, Jane, and the late Pete Duffy. Mike was born on November 14, 1943, in Southbridge, MA, to Stefanie (Kozyra) and Thomas L. Duffy, M.D. He attended Loyola Academy, The College of the Holy Cross, and Northwestern University Medical School, and completed his psychiatry residency at the University of Washington. He served as a physician in the U.S. Navy, including two years at Camp Pendleton, before spending the next 35 years practicing psychiatry with the Veterans Administration and in private practice in Kenosha, WI. Mike and Rosemary were longtime residents of Northbrook, IL, where they raised their four daughters. Curious by nature, Mike traveled internationally and to 49 U.S. states, carefully planning each trip and enjoying the route as much as the destination. He was a lifelong fan of Chicago sports teams and followed them with genuine enthusiasm. Known for his generosity, humor, and love of storytelling, Mike had a way of making people feel welcome and cared for. Services will be private. Those who knew and loved Mike are invited to raise a glass or share a story in his memory. In lieu of flowers, donations may be made in his memory to the National Brain Tumor Society at https://nbtsevents.braintumor.org/tmduffy.