Mark Steven O’Brien, age 72, of Grand Rapids, Michigan passed away May 21st, 2026, in his home. Born in Detroit on March 12, 1954, to Elizabeth (Politis) and Jerry O’Brien, Mark grew up with the spirit of a man who would go on to build something meaningful in every corner of his life. He ran a thriving medical practice and owned a warm and welcoming home for all of his friends. Mark earned his bachelor’s degree from the University of Michigan, a school he would cheer for with unwavering loyalty for the rest of his life — before going on to earn his Doctorate from Wayne State University. He further pursued a fellowship in Nephrology at Northwestern University in Chicago. He built his career as an internal medicine physician and was the proud owner of his own medical practice for over 20 years where he dedicated his life to the care of his patients. He even held the role of match maker by introducing two of his patients. They ended up getting married and Mark was the best man at the wedding!
Mark was the man who would truly light up when entertaining, who would run to fire up the grill without being asked and who knew how to make any occasion feel like a party. His dry sense of humor had a way of catching you off guard and making you laugh. He was equally at home tailgating before a Michigan game, cruising down the highway in his RV, or reading endless books about coding and computers. He even built his oldest daughter her first computer for college.
Marks love of adventure knew no bounds. He stood at the edge of the Cliffs of Moher in Ireland and kissed the Blarney Stone. He took to the open seas on countless cruises. He would return again and again to the waters of Mexico and Costa Rica — where he was happiest with a snorkel mask on his face or a line in the water while deep sea fishing.
He is survived by his brother Dan (Karen) O’Brien, sister Patricia Rice, and three children Bridget (Andrew) Freed, Kathryn O’Brien and Connor O’Brien, and wife of 25 years, Denise DeVries.
Due to the recent birth of Mark’s granddaughter Zosia Ashbrook Freed, a celebration of life will be held at a later date to be announced. In the meantime, in the spirit of Mark, we encourage you to go for a bike ride, play a round of golf or grab a drink with a friend.
Go Blue, Dad. Rest easy.