John D. Cahill IV, M.D.

John Donald Cahill MD IV loved life and lived a remarkably full one before dying of brain cancer at his home in Pelham, NY on December 8, 2023. He was 56. John was a loving husband, father, son, brother, nephew, cousin, friend, and physician. He traveled the world as a doctor, sailor, and adventurer, always connecting with people and nature. He was kind, compassionate, generous, and brave. His deep intellect, silliness, and energy were boundless.

Born on May 17, 1967, John was the eldest of Dr. John and Elizabeth (Stock) Cahill’s five children—a tight-knit crew of cascading “Irish twins.” His father practiced family medicine, and his mother was a Montessori school teacher. Raised in Pelham, New York with summers in Cambridge, Maryland, John was a true people person. At age five, he would drag his younger sister to the neighbors’ homes to chat them up over cookies and milk. 

He attended Pelham Memorial High School with an exceptional penchant for music, mischief, movies, and friendship. John blossomed intellectually at Catholic University in Washington, DC, studying philosophy, biology, and violin. He attended the Royal College of Surgeons in Dublin, Ireland for his first years of medical school and received his degree from the Icahn School of Medicine at Mount Sinai in New York City. He did his residency in Emergency Medicine at Brown University in Rhode Island, where he later became an adjunct professor. 

While on a semester with the Sea Education Association in college, John discovered a lifelong love of sailing. One summer, John was hired as a navigator to help deliver a sailboat from Long Island to Portugal. After three days of torrential storms outside the Azores and 24 hours in a lifeboat, they were rescued by a British Petroleum Oil Tanker. Never one to let his fears hold him back, John set sail on a small sunfish later that month and managed to sink it. Nonetheless, he kept sailing and became very skilled at it. These skills came in handy when pirates attacked him and his wife Rachel during their honeymoon in the Grenadines.

He met his wife, Rachel (Kelly) Cahill, a health and human services specialist, in 2000. More than 500 people attended their wedding, a testament to their many devoted friends and family. After some time in New York City, they settled in Pelham, NY to raise their two children John V and Claire. He treasured his children and delighted in their kindness, humor, and strong spirits. He was generous with his time and expertise, always willing to help those who needed medical advice, care, or friendship.

John loved a good party, a tall tale, and a simple pizza pie. He was often the last one to leave a gathering, lingering for the final drink, laugh, and story. He was equally well-versed in classical music and the Grateful Dead as he was in medicine.

He served as the senior attending physician in infectious diseases and emergency medicine at St. Luke's-Roosevelt Hospital Center/Mt. Sinai and as an assistant clinical professor in emergency medicine. For nearly a decade, he was also a doctor at the Ortum Missionary Hospital in northeastern Kenya, traveling there several times a year. This experience inspired John and Rachel to found the Center for Global Collaboration and Health Initiatives. 

Perhaps the greatest joy of John’s medical career was serving as the physician for the New York Philharmonic for 15 years. He accompanied the orchestra on their travels around the world with a medicine trunk. He cherished his friendships with orchestra members, staff, and Philharmonic soloists. 

John was a member of the Celtic Medical Society, which honored the Cahill family with its Healers Award for contributions to Celtic ideals and adherence to the belief that the best way to judge society is how they care for the least privileged and most in need. He received the Cullman Family Award for Excellence in Physician Communication, was regularly listed as one of New York’s Top Doctors, and was honored by Mt. Sinai for Excellence in Emergency Medicine. His research was published in some 21 peer-reviewed publications.

His philanthropy included creating the Leo F. Stock Impact Scholarship at Catholic University, named after his grandfather who also attended the school, to support undergraduate students involved in their communities.

He was diagnosed with glioblastoma brain cancer in 2022. John had two brain surgeries and multiple rounds of radiation, chemotherapy, and immunotherapy. He and his family made the most of their time together between treatments, traveling whenever possible. Many thanks to the dedicated teams at Mt. Sinai, Memorial Sloan Kettering, Osborn Home Care, Hospice of Westchester, and friends and family who helped care for him.

He is survived by his spouse and children (Rachel, John V, and Claire), and by his siblings, their spouses and children Sara Cahill (Alyx Hamlin-Cahill), Elizabeth Cahill (Robert, Anna, Leo, and Noah Babboni), Mary Cahill, and James Cahill (Mufridah Nolan). He is preceded in death by his mother Elizabeth “Betsy” Stock Cahill and his father John Cahill III.