Mary Brewster Kennedy of Cambridge and Vineyard Haven died following a stroke on Nov. 16 in Cambridge. She was 97.

She was the daughter of Florence Besse Brewster Ballantine and Kingman Brewster Sr. and the stepdaughter of Edward Ballantine. She was the only sister of the late Kingman Brewster Jr., president of Yale University and ambassador to the Court of St. James.

Mrs. Kennedy grew up in Longmeadow. She was a graduate of Miss Hall’s School and Smith College, class of 1936. While a graduate student at the University of Chicago in 1939 she married Carvel E. Collins, who became a professor of American Literature at MIT and an authority on William Faulkner.

After divorce, Mrs. Kennedy married Robert Woods Kennedy, a Cambridge architect, in 1958.

She ran her own design business, Kennedy Interiors, in Cambridge until age 87. A devoted member and former president of the Cambridge Plant and Garden Club, she also served as a conservation commissioner for the city of Cambridge and was instrumental in developing the jogging trail around the Fresh Pond Reservoir, among other projects.

She loved travel, the fine arts and design, classical music and Martha’s Vineyard. Known for her beauty, discerning taste and progressive social values, she faced the many challenges of her 97 years with grace, charm and forbearance.

She was a beloved matriarch to all of her blended family.

She is survived by her daughter, Lucy E. Collins, MD and son in law, Harry Davidow of New York city and Vineyard Haven, a step-granddaughter and two great-grandchildren; three stepsons, Duncan Kennedy and his wife Mopsy of Cambridge, David Kennedy and his wife Nadia of Montclair, N.J., Charles Kennedy of San Diego, Calif., seven step-grandchildren and six great-grandchildren. She is also survived by five Brewster nieces and nephews, devoted friends and many cousins of the Besse clan, including the Rev. and Mrs. Alden Besse of Vineyard Haven.

Special thanks go to Sheryl Enos, CNA of Oak Bluffs, whose excellent care of Mrs. Kennedy during her visits to the Vineyard in her last years, made it possible for family to spend time with her on the Island she loved.

Interment will be private in the Oak Grove Cemetery in Longmeadow. A memorial service is being planned for the spring.