Along with her husband, literary scholar John Lorne Campbell, Shaw helped lay the foundation for both the modern Scottish Gaelic Renaissance and heritage language revival using Scottish Gaelic-medium education The youngest of five sisters, Shaw was born in her family's "substantial mansion",[1] built from homemade bricks in 1829,[2] in Glenshaw, Pennsylvania.

[5][6] Margaret's great-grandfather, Thomas Wilson Shaw, Sr., lived to be ninety-six and often told the story in his old age of how his own father had lifted him up on his shoulders to see George Washington ride by on a white horse during a visit to Pittsburgh.

"[10] Margaret's mother Fanny Maria Patchin[11] was "a New England Yankee", whose Puritan ancestors had arrived in the Colony of Connecticut in 1640 and eventually migrated to Bennington, Vermont.

Margaret later recalled her mother as a woman for whom "breeding and mental ability were what mattered" and who accordingly "found the wealth, without the distinguished minds, of the Pittsburghers difficult to take.

"[21] While studying at New York University, she returned to Scotland in the 1920s and was overjoyed to once again hear the songs she had heard at St. Bride's, but sung in the original Gaelic by native speakers of the language.

[22] After her plans to be a concert pianist were thwarted by rheumatism,[23] Shaw switched, with the encouragement of Nadia Boulanger and Eileen Costello and much to her family's horror, from medicine to the new field of ethnomusicology and began full-time folk song collecting.

[24] She realized over time that the study of Classical music had not prepared her for collecting from traditional singers in Celtic languages, whose repertoire uses a completely different system of scales, tonalities, and modes.

[3] Shaw's photographs highlighted the working lives of women in South Uist, who played crucial roles in their families and local economies.

On a rainy evening in 1934, Campbell was introduced in typically Scottish style as "Young Inverneill" to Margaret Fay Shaw by the manager of the Lochboisdale Hotel on South Uist.

The Campbells also persuaded Jonathon G. MacKinnon [gd], the former editor of the literary magazine Mac-Talla, to introduce him to Gabriel Syllibuy, the Chief of Cape Breton's indigenous Mi'kmaq people.

But she always insisted that her favorite English-language Presbyterian hymns from her childhood, such as Charles Wesley's Christ the Lord is Risen Today, be sung during Low Mass at St Columba's R.C.

[38] After years of taking care of her husband during multiple mental health struggles, Shaw was finally able to find enough time to complete her life's work: Folksongs And Folklore Of South Uist, which was published by Routledge & Kegan Paul in 1955.

[31] In a 2004 article about Shaw for The Guardian, Brian Wilson wrote of the book, "Not only was it a scholarly presentation of the songs and lore which she had written down during her sojourn on the island, but also an invaluable description of life in a small crofting community during the 1930s.

"[43] In advance of St Columba's Day, 9 June 1963, Shaw learned that Bishop Stephen McGill of the Catholic Diocese of Argyll and the Isles, a Glaswegian who preferred Anglo-Saxon princess and Queen St Margaret of Scotland as a national saint, had refused to celebrate the 1,400th anniversary of St. Columba's arrival from Gaelic Ireland as a Christian missionary to Scotland.

Deciding to discreetly defy the Bishop with a celebration of their own, Shaw and the parish priest of St. Columba's Catholic Church upon Canna arranged for a Tridentine Solemn High Mass followed by Eucharistic Benediction for the enormous number of pilgrims who arrived aboard boats from Rùm, Eigg, and Mallaig.

[44] Following the Second Vatican Council, Campbell and Shaw disliked the abandonment of the Ecclesiastical Latin liturgical language and the subsequent introduction of the Mass of Paul VI in the vernacular.

[19][46] The Campbells donated their house and its contents to the National Trust for Scotland in 1981, but Shaw continued to live there even after her husband's death while they were on holiday at Villa San Girolamo in Fiesole in Italy in 1996.

[47] The tribute to her work that meant to most by far to Shaw was made, in response to both the 1955 publication of Folksongs and Folklore of South Uist and Shaw's role in helping to inspire a Scottish Gaelic language revival, as part of a Gaelic poem in praise of (Scottish Gaelic: Maighread chòir, Bean uasal Eilean Chanaidh) ("Honest Margaret, the noble Lady of the Isle of Canna") by South Uist Bard Fred T. Mac 'ill Iosa (Fred Gillies): In 2007, scholars gathered in a conference in her honour in South Uist called "Gleann na Ceolraidh" ("Glen of the Muses").