Dede Lawson-Johnston died peacefully on Jan. 28 after a 70-year love affair with her surviving husband Peter and decades of devotion to their family.

She had been a longtime summer resident of Edgartown.

She was born Dorothy Hammond in Owings Mills, Md., to Donald and Molly Hammond. She developed a signature mischievous wit at the nearby Garrison Forest School. In 1950 she married Peter, now honorary chairman of the Solomon R. Guggenheim Foundation and chairman of the Harry F. Guggenheim Foundation, and together they extended the Guggenheim family legacy in art and philanthropy.

She was a prolific hostess and fundraiser for many causes including the Guggenheim Museum, serving as gala co-chairman on several occasions, as well as the Princeton Medical Center, New Jersey Neuropsychiatric Institute and Planned Parenthood. She was known for her overwhelming generosity and hospitality to legions of family and friends, and especially enjoyed playing tennis, bridge and dancing.

She was a member of Pretty Brook Tennis Club, The Colony Club, Edgartown Yacht Club, The Present Day Club, The Contemporary Garden Club, Bedens Brook Club and The Jupiter Island Club. More than anything, she will be loved and remembered as the supportive and deeply loyal matriarch of a clan that includes four surviving children and their spouses, Wendy and Tom McNeil, Tania and Sam McCleery, Peter and Karen Lawson-Johnston, Mimi and Nat Howe, her sister Mary (Dumpsy) Hackney, more than 20 grandchildren and great-grandchildren, and a lifetime of beloved dogs of every shape, size and demeanor.

Her extraordinary life will be celebrated at Christ Memorial Chapel in Hobe Sound, Fla., on Monday, Feb. 4, at 1 p.m. Family members will wear pink in honor of her favorite color.

In lieu of flowers, donations can be made to the Garrison Forest School (gfs.org; 300 Garrison Forest Road, Owings Mills, MD 21117).