She was a bridesmaid at the wedding of Prince William and Catherine Middleton in 2011 and accompanies members of the royal family to public events.

[1] She is the daughter of David Armstrong-Jones, 2nd Earl of Snowdon, who was styled as Viscount Linley at the time of her birth, and The Honourable Serena Stanhope.

[1] She grew up at her family's three homes: a flat in Chelsea, London, a cottage on the grounds of the Daylesford Estate in Gloucestershire, and the Château d'Autet in France.

[8][9] Lady Margarita took life drawing, pottery, and watercolour painting courses at a small art school in Oxford.

[8] In September 2022, Lady Margarita enrolled as a student at La Haute École de Joaillerie in Paris to study jewellery design, stonesetting, and wax carving.

[13] That same year, she accompanied her aunt, Lady Sarah Chatto, to the 60th birthday brunch for Charles, Prince of Wales at the Goring Hotel.

[15] Every year she does the "Christmas walk" with the royal family to St. Mary Magdalene Church and attends the Easter service at the private chapel of Windsor Castle.

[8] In 2023, she was the May cover girl of Tatler, photographed by Luc Braquet, and was featured in a spread in the magazine modelling couture gowns.