James C. O’Sullivan (Jim), 87, of Colrain Road, Greenfield died peacefully Sunday 6/15/25 at Baystate Franklin Medical Center in Greenfield. He was born in Greenfield on November 20, 1937, the son of Michael and Theodora (Mazur) O’Sullivan. Jim graduated from Greenfield High School in 1955, received his undergraduate degree from the University of Massachusetts in 1962 and continued his education, receiving a Law Degree from Boston University in 1965. After passing the Bar Exam, Jim opened his law practice in Greenfield, where he enjoyed practicing law for more than 50 years. 
Jim had a passion for golf and was a member of the Country Club of Greenfield for more than 50 years. In addition, he enjoyed bowling, softball, and trips to Saratoga and Hinsdale Racetracks. He was an avid New England sports fan and especially enjoyed watching the Red Sox.  Jim was liked by all, had a great sense of humor and always had a story to tell. He looked forward to his weekly card games with his lifelong friends. 
Jim married the love of his life Sandra Harper on June 16, 1962. Family was everything to Jim. Besides his beloved wife of 63 years, together they raised 3 children:  James C. O’Sullivan, Jr. and his wife Kelly of York, Maine; Jacqueline M. O’Sullivan of Montague; and Sean M. O’Sullivan and his wife Kathleen of Greenfield. He was the proud grandfather of seven grandchildren: Christopher and Matthew O’Sullivan; Shelby and Justin Sayer; Sarah, Amy and Sean O’Sullivan, Jr.
Jim had 3 brothers and 2 sisters. He is survived by his brothers Gary O’Sullivan of Florida and Francis O’Sullivan of Greenfield.  Jim was predeceased by his brother Michael O’Sullivan of California, his sisters Cielle Sabean of Greenfield and Mary Matthews of Greenfield. 
There will be no calling hours. 
In lieu of flowers, memorial contributions can be made to the Franklin County Sheriff’s Office Regional Dog Shelter, 10 Sandy Lane, Turners Falls, MA 01376.
Arrangements are under the direction of the Kostanski Funeral Home. For condolences, please visit www.kostanskifuneralhome.com.