Marianna Hilliard Mead O’Brien died peacefully on Jan. 9 surrounded by her loving family on Martha’s Vineyard. She was 90.

Born in Aiken, S.C., on March 28, 1930, to George Houk Mead of Mead Paper Company and Elsie Talbott Mead a philanthropist, Marianna was raised between Aiken, Washington, D.C. and Dayton, Ohio. She was the youngest of six children (Louise, George, Talbott, Nelson, and Katharine) where love of family and a life of service to others were instilled from an early age.

She became widely known as Muffin when attending the Garrison Forest School, and spent summers serving as a courier for Frontier Nursing in Kentucky. Muffin attended Briarcliff College before her happy working days at Harper’s Bazaar in New York. She met Frank (Junie) O’Brien Jr. at Camp Keewaydin and they married June 18, 1955 in Dayton. The O’Briens shared a full and happy life raising their four children and serving as dorm parents, teachers, advisors, and mentors at the Groton School. Muffin played an integral role in the coeducation of Groton School and from 1974-1980 served as assistant to the headmaster for special events and head of student activities. When not racing around campus cheering on hockey and baseball teams or singing in the school choir, Muffin was whipping up her signature chocolate chip cookies, waffles and Aunt Martha’s casseroles — all consumed by ravenous teenagers during parlor games and advisee meals.

After retiring from Groton in 1980, the O’Briens relocated to Boston where they founded O’Brien Associates, an educational consulting firm to guide families in secondary school placement. Muffin was a trustee of Miss Porter’s School in Farmington, Conn., from 1976-1981 where she also served as interim head of school from 1992-1993.

Never one to be idle, Muffin was also a trustee of Applewild School, The Boys and Girls Clubs of Boston, Massachusetts Society for the Prevention of Cruelty to Children (MSPCC), and the Council for Religion in Independent Schools (CRIS). She further contributed to the Epiphany School, Mother Caroline Academy, Beacon Hill Village, and the Chilton Club where she served as Governor, then President from 1994-1997. At Trinity Church, she was a lay reader, member of the Befrienders group, and on committees for The Trinity Hospice Associates and the Sherrill House. Muffin, Junie and their family enjoyed Martha’s Vineyard for 60 years, entertaining family, friends and former students on their Havoc House porch overlooking the Edgartown Harbor. Sailing with her brother Nelson’s family, cocktail cruises, beach picnics, singing toasts and dinners at EYC with her lively friends brought Muffin endless joy. As a grower and giver of love all of her life, Muffin tended her magnificent flower garden, choosing select blooms to display on the St. Andrew’s Church altar down the street.

The O’Brien family greatly appreciates Muffin’s compassionate caregivers throughout the years.

She was predeceased by her dear husband of 57 years. She is survived by her four loving children, Dede O’Brien

Baker and her husband Jack, Elsie O’Brien Aubrey and her husband Stever, Louise O’Brien, and Frank O’Brien 3rd and his wife Amy; her 10 adoring grandchildren, Annie, Alex and Carly Baker, Lilah and Tyler Aubrey, George and Julia Scully, Jay, Liza and Trevor O’Brien; and three great-grandchildren, Weylin and Finley Scully and Brooke Baker.

The family will hold a private interment service and looks forward to a larger memorial gathering at a later date to celebrate her wonderful life.

Donations can be made to Miss Porter’s School for The Marianna M. O’Brien Head’s Discretionary Fund c/o Jose Lugo, Manager of Gift Services, Miss Porter’s School, 60 Main St., Farmington, CT 06032 or www.porters.org/annual-fund.

Correspondence to the family can be mailed to P.O. Box 5045, Edgartown MA 02539. For online guestbook and information, please visit www.ccgfuneralhome.com.