Michael B. O’Sullivan M.D.

Michael B. O'Sullivan, M.D., age 88, passed away peacefully at Charter House in Rochester, MN, on April 20, 2024. The sixth of seven children, he was born to Nora (née Ahern) and Mícheál Ó'Súilleabháin on August 20, 1935, in Tralee, Co. Kerry, Ireland. His upbringing in Listowel instilled a lifelong love of learning, a strong work ethic, a competitive spirit, an appreciation of music as the universal uniter, and a steadfast pride in his Irish heritage.
Michael graduated from medical school at University College, Cork, Ireland, in 1959 and began his postgraduate studies in Buffalo, NY. The death of his father took him back to Ireland shortly thereafter. He married Margaret Stack on January 25, 1962, and returned to the U.S. to serve in the Armed Forces at Maxwell Air Force Base in Montgomery, AL, as Captain from 1962 to 1964. Upon fulfilling his military commitment, he and Margaret moved to Rochester, MN where Michael began his fellowship in Hematology and Pathology at Mayo Clinic. He joined the staff as a consultant in Hematopathology in 1969.
In his early career, he led the development of the regional laboratory program to provide laboratory services to small hospitals in the region around Rochester with the goal to improve quality of care. This strategy grew and is now Mayo Clinic Laboratories, serving patients and healthcare organizations worldwide. After 15 years as Chair of Lab Medicine and Pathology, Michael led the development of Mayo Health System which acquired physician-led community clinics and hospitals within the region to be an extension of Mayo Clinic and to enhance clinical practice and patient care in those communities. Ready to climb one last mountain for Mayo Clinic, in 1997, Michael headed west as the CEO of Mayo Clinic in Arizona, where he led the practice to success in the competitive Scottsdale market and oversaw the successful opening of the Mayo Clinic Hospital. He retired from Mayo Clinic in 2002.
Throughout his life, Michael was regarded as a visionary leader, for his disarming personality, and for his powers of persuasion. He and Margaret hosted countless dinner parties and gatherings for dignitaries and friends alike and welcomed all with warmth and gracious hospitality. His after-dinner singsongs were legendary. Many of these gatherings were held at Michael and Margaret's beloved lake home on Spider Lake near Hayward, Wisconsin. He loved everything about his Heaven-on-Earth and was particularly proud of the times he strapped on his skis to complete 10 Kortelopets and 1 Birkebeiner. Spider Lake was Michael and Margaret's retirement home until they moved to Charter House in 2019.
Michael leaves behind his wife of 62 years Margaret, his daughters Nora (Dan Nelson), Deirdre (Mark) Palmer, and Finola (Mike Busch), sons Paul and Stephen, grandchildren J.P. Salvatierra, Olivia Nelson, Helen, Anthony and Caroline Palmer, Charlie, Spencer and Michael Busch, and Desmond and Myles O'Sullivan; sister Sr. Lelia (Bríd) O'Sullivan and brother Joseph O'Sullivan; sisters-in-law Agnes Andrews and Marie O'Sullivan; and numerous beloved nieces and nephews. He was preceded in death by his parents, brothers Seamus, Patrick and Denis and sister Maura Kelly, sisters-in-law Sr. Rosa Stack and Josephine O'Sullivan, brother-in-law Eamonn Kelly, niece Ann Marie Lynch and nephew Brian Kelly.
Michael's family would like to extend our sincere gratitude to the excellent care he received at the Mayo Clinic, in particular from Dr. Eric Edell and Dr. James Hill, from his Mayo Hospice team, and from his caregivers Mini Collett, Heidi Coyer, Kim Yokiel, and in particular Grace Ibsen and Amy Allen who provided tender and affectionate care in his last hours.
A wake will be held in the River Park Chapel at Macken Funeral Home on Thursday, April 25 from 5-8 p.m. where a singsong will send him off in style at 7:00PM. The funeral will take place at the Co-Cathedral of St. John the Evangelist on Friday, April 26 at 10:00 a.m. with The Rev. Msgr. Gerald A. Mahon officiating. Visitation will begin at 9:00 a.m. in the gathering space at Co-Cathedral of St. John the Evangelist. Please join the family in singing Michael's favorite hymns at 9:45AM in the church. In lieu of flowers, donations may be made to the Michael B. O'Sullivan M.D. Medical Technologist fund at Mayo Clinic or to the charity of the donor's choosing.
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