Obituary of John "Jack" J. O'Brien

John “Jack” O’Brien – a man of quiet strength, deep humility, quick wit, good hearted humor and steadfast love for his family – passed away peacefully in bed holding his wife’s hand, at home on Saturday, April 12, 2025. He was 90 years old.

Jack was born in Cambridge, the 7th child of Daniel F. and Mary A. (Foley) O’Brien. He was born with the kind of character every parent hopes to see in their children. Jack lived a life defined by integrity, kindness, and commitment. He was the kind of man who never sought the spotlight, but whose presence lit up every room with warmth and steady reassurance. A devoted husband, father, grandfather, great-grandfather, veteran, and friend, Jack left behind not just memories, but a legacy of decency and devotion.

Jack was a proud veteran of the United States Army, having served his country honorably during the Korean War. His service, like everything in his life, was carried out with diligence and humility. Upon earning his Honorable Discharge, he met the love of his life, Eileen Mahoney. Their meeting marked the beginning of what would become an extraordinary 65-year journey of love, partnership, and mutual devotion. Theirs was a bond that served as a model for their children, grandchildren, and all who knew them.

Together, Jack and Eileen built a life in Burlington, where they raised their family and formed lasting friendships. Jack pursued an education at Franklin Pierce University, earning an associate’s degree in civil engineering, a decision that would lead him to a long and fulfilling career with Hayes Engineering.

Though he took his career seriously, Jack always understood that family came first. He was a present and dedicated father, never missing an opportunity to support his children in their pursuits. Whether it was helping with college tuition or lugging boxes during yet another move into a dorm room or first apartment, Jack showed up. Always. His love didn’t have to be declared, it was demonstrated, day in and day out, through acts of service, quiet sacrifices, and a consistency that became the foundation of his family’s life.
Jack found joy in the simple pleasures: a freshly mowed lawn in his beloved garden, a good book in hand, and a highball or a well-made Manhattan to cap off the day. He was an avid reader, drawn to the kinds of stories that mirrored his own values, resilience, purpose, and depth. He loved dogs, his own and everyone else’s, and never left the house without a few Milk-Bones in his pocket, ready to offer a treat and a scratch behind the ear to any pup he met on his walks. In Jack’s world, everyone, two-legged or four, deserved a little kindness.

In his free time, he enjoyed following all the Boston sports teams via the Boston Globe, radio and TV (although they broke his heart sometimes).  

In retirement, Jack found camaraderie and peace on the golf course. He was an enthusiastic golfer who relished time spent on the greens with a close-knit group of lifelong friends and family – even broke 80 sometimes!  These afternoons on the course involved laughter, competition, and created lasting memories.

Jack was also a past member of the Knights of Columbus, where he deepened many of his friendships and gave back to his community in quiet, meaningful ways – and truly enjoyed their annual golf tournament.
His heart always belonged to Eileen. Their marriage was a masterclass in love, built on mutual respect, shared values, and a deep, abiding care for one another. He called her “his bride” for all 64 years that they were married.  He told her loved her every day, and never left the house without giving her a kiss. 

The two loved to travel together. Jack always held a special place in his heart for the Saint Islands (St. Barts, St. Kitts, St. Martin, and St. Lucia) and his travels to Europe including his ancestral homeland Ireland. 

As the years passed and life brought its inevitable changes, Jack remained by Eileen’s side, ever her protector and partner. When Eileen began to lose her eyesight, Jack didn’t miss a beat. He seamlessly stepped into a new role, ensuring her comfort, dignity, and independence. He became her eyes, her helper, and her unwavering companion, tending to her needs with the same quiet grace that had defined their life together. It was a love story written not with grand gestures, but with small, daily acts of devotion, each one more powerful than words.

In addition to his parents, Jack was predeceased by his siblings Catherine Perry, Dede Higginbotham, Joanie Sutton, Helen Linnehan, William O’Brien, Daniel O’Brien, and Chrissy Moniz, as well as his best friend and “brother”, partner in all shenanigans, Jerry Crocker.
He is survived by his loving wife Eileen Mahoney O’Brien, of Burlington,  his adoring children, John “Jack” O’Brien Jr. and his wife Jennifer of Chicago, IL, Peter O’Brien and his wife Sharon of Burlington, Beth Anne Reith and her longtime companion, Charles Veneziano of Burlington, Julianne Esposito and her husband Jed of Denver, CO, his former son in law, Scott Reith of Burlington,  grandchildren, Samantha and Syndey O’Brien, Max O’Brien, Christine Munroe and her husband Cody, Spencer and Leighton Reith, and Nicolas and Graham Esposito, many beloved nieces and nephews, as well as a new great-grandson, Grayson Munroe, whom Jack was overjoyed to be able to hold for the first time last week, which will remain a treasured memory for all.
All of his children have said for years that everyone needs a “Jack O’Brien” in their life and his family and friends were lucky enough to have the actual one. 

At his request, all services will be private and at the convenience of his family. Arrangements are by the Edward V. Sullivan Funeral Home, Burlington. To view his memorial slide show or leave a condolence for his family please visit www.sullivanfuneralhome.net.