Diana Stott Cassidy, 65, of Randolph, Massachusetts, passed away on January 8, 2026, surrounded by love. She was born on January 1, 1961, in Plymouth, Massachusetts to Thomas and Mary Stott.

Diana held a unique place in local history as the first child born in Plymouth County in 1961, an event that earned her newspaper coverage and a bit of lifelong notoriety.

Diana grew up first in Duxbury where the family had Camp Holly Hill. Then New Canaan, CT and next South Egremont, where she attended The Berkshire School. She went on to attend the University of Bridgeport.

Diana married Paul Cassidy, with whom she had two children, Megan and Stephen. Though later divorced, Diana devoted herself fully to raising her children as a working single mother in Quincy, instilling in them resilience, independence, and a deep sense of family.
A biotech operations powerhouse, Diana built a highly respected career marked by grit, intelligence, and relentless energy. She was admired for her leadership, trust, work ethic, and ability to get things done. She was actively working as Head of Operations at Stellular Bio in Watertown, a role she was passionate about.

Above all else, Diana was a caretaker. She loved family, cooking and experimenting with new recipes, travel, DIY home renovation, gardening, entertaining, and taking care of “her people”. She adored animals and cared for a small homestead at her Randolph home, complete with dogs, goats and chickens, which brought her immense joy.

Diana was known and admired by many, lovingly called Mémé, Di, Auntie Diamond, and Lady Di. She is survived by her children, Megan Cassidy and Stephen Cassidy, daughter in-law, Sarah, and beloved granddaughters, Madyson & Elowen. She is also survived by her siblings Pam, Randi, Wendy, and Tom, along with many nieces and nephews who affectionately called her “Auntie Di.” And the close friends who were also family, who all together loved to spend time with her at The Farm and be in her orbit.

Diana will be remembered for her boundless energy, fierce love, generosity of spirit, and the way she showed up, fully and fearlessly, for the people she loved. Her presence filled rooms, her laughter lingered and her legacy lives on in the family, friends and all whose lives she touched.

A funeral will be held on Saturday, March 7th at 10:30am at the First Congregational Church of Braintree. Family and friends are welcome.

In lieu of flowers, donations in Diana’s name can be made to the MSPCA at Nevins Farm.