Waterville: Gregory Leonard Theriault, beloved father, grandfather, brother, uncle and friend, died suddenly from complications of congestive heart failure on August 25, 2026. He was 76 years old.

Born the oldest of three children (and the only son) to the late Leonard J. Theriault and Theresa Drouin Theriault on August 22, 1950, in Waterville, Greg graduated from Sacred Heart School, Waterville High School, and Thomas Business College before earning his MBA from Southern New Hampshire University. Always a savvy businessman, Greg spent 34 years in senior finance positions with the Jackson Laboratory, Loring, Short and Harmon Office Supply and R.C. Moore Trucking. More recently he embarked on entrepreneurial endeavors, running two different businesses, one in Biddeford and the other in Fairfield.

In addition to his parents, Greg was predeceased by his granddaughter, Summer Vose. Survivors include his longtime partner, Judy Ladd. He leaves three beloved daughters, Erica White (and husband Dan White) of Jefferson, Maine, Heather Vose (and partner Jon Cota) of Londonderry, New Hampshire, and Heidi Vicneire (and husband, PJ Vicneire) of Embden, Maine. Grampie Greg leaves seven grandchildren: Basel, Ava, Skyler, Landon, Nicholas, Makayla and Lucas. He also leaves his sisters, Jeri Theriault (and husband Philip Carlsen) of South Portland, and Blanche Theriault (and partner Gene Rossignol) of Waterville, seven nieces and nephews and many cousins.

In high school Greg was a member of the National Honor Society and president of the inaugural Catholic Youth Organization in the Sacred Heart Parish; he even traveled to the CYO national convention in Miami, Florida. It was also in high school that Greg parlayed his eight years of piano lessons into playing keyboard for rock groups, such as the popular Imposters and The Coachmen who won the Battle of the Bands in 1968. He continued to make music, largely funding his college expenses by playing weekend gigs.

Greg was an avid Red Sox fan and a coin collector. He loved old cars and remodeled a four-unit property in Westbrook, doing most of the renovations himself. He sold that property and relocated to his hometown of Waterville in 2022.

More than anything else, Greg loved his family. A dedicated father and grandfather, he attended his grandkids’ soccer games and other events, advised his daughters on their new businesses, and acted as a friend and mentor to his nephews, helping one to rebuild an old car and talking shop with another who had followed him into the accounting field. Since moving back to Waterville, he also reconnected with two elderly aunts and several cousins.

Greg had a big personality, strong opinions and a zest for life. He will be missed for his generosity, his infectious laughter, and signature grin. A service will be held on Tuesday, September 8,2026 at 10:00am at Notre Dame Church on Silver Street in Waterville.

In lieu of flowers, donations can be made in his memory to: Maine General Office of Philanthropy, PO Box 828, Waterville, ME 04903.