Harry Richard Clark Jr., 69, of Townsend, MA, formerly of Concord, MA, died on Tuesday, August 12, 2025, in Leominster, MA.

Born in Hoboken, New Jersey on April 9, 1956, he was the son of the late Harry R. Clark and Jane F. Clark, and the eldest of six children.

Harry attended Concord-Carlisle High School where he had a great group of friends. He excelled in academics, particularly science and math, ran track, and offered steady guidance to his younger siblings. As the eldest, Harry embraced a unique role as both protector and teacher, marked by a nurturing spirit and the deep bonds he forged with each of his siblings. He then attended college at both UMass Amherst and UMass Boston where he earned a Bachelor of Science in Physics.

Early in his career, he founded Townsend Science & Engineering, leading Department of Defense research efforts and serving as principal investigator on a successful SBIR grant.

Most recently, and with great pride, he worked in the Advanced Imaging Technology group at MIT Lincoln Laboratory for over 20 years. A gifted physicist and inventor, Harry devoted his career to advancing imaging, materials science, and aerospace technologies.

Though often modest about his accomplishments, Harry's work was recognized in national awards and ceremonies, including The Sentinel's Enterprise award presented by Senator Edward M. Kennedy in 2000. At Lincoln, he co-developed liquid crystal thermal imaging systems that earned the lab's prestigious Best Invention Award in 2010. Harry was granted 12 U.S. patents and authored 38 publications. Harry was well known for his relentless work ethic, deep technical knowledge, advanced troubleshooting skills, and friendly, unshakable demeanor, along with an uncanny ability to get things done.

Outside the lab, Harry was a true New Englander through and through; an avid fan of the Patriots, Notre Dame football, and a faithful patron of Dunkin' Donuts (large, regular, of course). He had a love for sports, especially youth basketball and softball, which he coached with heart and dedication. Whether cheering on his kids in the hockey rink or on the court or applauding from the audience at countless dance recitals, Harry never missed a chance to support the people he loved.

Harry was a dedicated "Papa" to three grandchildren who adored him and who he loved with all his heart. He found peace in the outdoors, especially while camping with family and friends.

Harry was a natural caregiver, selfless, and dependable. He was the kind of person who showed genuine gratitude for even the smallest kindness. You could always count on him for a rave review of any meal cooked for him ("Fantastic!" "Best Evah!"), and for his presence: kind, practical, and reassuring. He made sure everyone around him felt safe, heard, and cared for. His generosity, humor, and loyalty will be deeply missed and long remembered.

Harry was predeceased by his father, Harry R. Clark; his mother, Jane F. Clark; and his brother, Thomas Clark.

He is survived by his children, Katherine Clark of Lunenburg; Elizabeth Clark and her fiancé Ben of Watertown; and Zachary Clark of Quincy; his three grandchildren, Madison, Mason, and Eleni; and his former wife and friend, Susan Clark of Devens.

He is also survived by his siblings, Jane Cullinane and her husband Chris of Palmyra, VA; Michael Clark and his wife Cathy of Lunenburg; Joseph Clark and his wife Kim of Virginia Beach, VA; and Judith LaRocca and her husband Peter of Concord, as well as many nieces, nephews, and cousins.

Family and friends are invited to gather for visiting hours on Friday, August 22nd from 4 to 7 pm at the Dee Funeral Home, 27 Bedford Street, Concord Center. Harry's Funeral Mass will be celebrated on Saturday, August 23rd at 10 am in St. Bernard's Church at Holy Family Parish, 12 Monument Square, Concord Center. Please click here to view the church live stream, for those who wish to attend the Mass remotely.  Burial will follow at St. Bernard's Cemetery, Concord.

We invite you to honor Harry's memory through a donation to the Brigham and Women's Hospital Vascular and Endovascular Surgical Fellowship . Your gift will help support the education and training of the next generation of vascular surgeons, advancing early detection and treatment of life-threatening vascular conditions like the one that claimed Harry's life.  A devoted father, proud grandfather, loyal brother, and faithful friend, Harry lived a life defined by quiet strength, generosity, and love. He was taken from us far too soon, and we hope to raise awareness of abdominal aortic aneurysm (AAA).

Arrangements are entrusted to Dee Funeral Home & Cremation Service of Concord.