Mary (White) Denneen of Quincy, passed away peacefully at age 87 on September 21 after a brief illness.

A lifelong resident of Quincy, Mass., Mary graduated from North Quincy High School in 1957, married William Denneen in 1962, and raised four sons. She was active in the community and an advocate for public education, chairing the Citywide Parents’ Organization in the 1970s. In her early career, Mary was as an executive assistant in industry and at the FAA at Logan Airport; after raising her sons, Mary worked at Tufts New England Medical Center, where she served as the Director of Clinical Research Administration prior to her retirement in 2003.

Mary’s family was at the heart of her long life, and she was a kind, loving member of a large, growing family. She was the youngest of 7 children and remained close to her siblings throughout their lives. Mary and her husband Bill met in middle school and were married for 64 years, sustaining a loving and supportive marriage that was admired by all. As her sons married, she welcomed their spouses and families to be part of her family, as she had always done with her sons’ many friends, who together enriched her life.

Perhaps Mary’s favorite role in life was as Nana to their 7 grandchildren, who she adored and admired as they grew and became young, independent adults. She was especially proud to have 5 granddaughters after raising 4 sons. Throughout her life, Mary was also close to her cousins, nieces and nephews, and great nieces and nephews, and loved spending time in Marshfield in summers, where many in the White family would spend time as she had in her childhood. Mary also had many dear, lifelong friends from childhood, neighbors and work colleagues who were an important part of her life.

Mary was bright, independent, optimistic and forward-looking. She was strongly progressive, caring deeply about issues that impact people and society broadly. She had courage of conviction to advocate and share her beliefs, and a genuine interest in engaging with people about important issues. Her optimism was grounded in her positive outlook and in her ability to recognize and bring out the best in people.

In addition to her beloved husband, William, Mary is survived by three sons and their spouses, Mark Denneen and Anthony Coyle of Boston; Bill and Suzanne Denneen of Baltimore; Jeff and Anne Denneen of Atlanta; and her daughter-in-law, Jen Trynin of Watertown, along with seven grandchildren: Henry, Maeve, Ruby, Darcy, Gracie, Rachel and Liam Denneen. She is also survived by her sister, Dorothy O’Brien, of Weymouth. Mary was pre-deceased by her eldest son, Michael, in 2018; by her parents, James White and Marion Payson White; her siblings, James White, Charles White, John White, Jane Daley and Marion Kiernan; and several dear nieces, nephews and friends.

A celebration of Mary’s life will be held on September 28th and 29th, with visitation at Keohane’s Funeral Home, 785 Hancock Street in Quincy on Monday from 4-7 p.m.; and a funeral mass at Sacred Heart Church at 386 Hancock Street, Quincy, on Tuesday at 10:00 a.m. Burial will be at Blue Hill Cemetery, with a reception to follow.

In lieu of flowers, donations may be made in Mary’s memory to Project Alive, a non-profit organization focused on research, advocacy and family support for people like her grandson, Liam, impacted by Hunter Syndrome; or to the Thomas Crane Public Library, 40 Washington St., Quincy, MA 02169.