Moore made her stage debut starring as Casilda in the Gilbert and Sullivan hit, The Gondoliers, in 1889 at the age of 17 and stayed with the company for two years.
After touring with Edwardes's company in musicals, she returned to England and light opera later playing the role of Scent of Lilies in The Rose of Persia (1899) and starring in Florodora (1900–01) and My Lady Molly (1903), among other West End shows.
[3] There she created the leading role of Casilda in The Gondoliers, the last great Gilbert and Sullivan hit, which opened at the Savoy Theatre on 7 December 1889.
"[4][5] She related her first-night experience:I had to make my first entrance in a gondola, with my back to the audience; and when I turned round to get out of it and faced the house my feelings were such that I shall never forget.
The Times wrote that she "has a delightfully fresh voice... she sings with very good taste and gives distinct promise of becoming a very acceptable actress; her appearance is extremely taking, and on the whole, a more successful début has not recently taken place".
Her older sister, Jessie Moore, who sang with one of D'Oyly Carte's touring companies, replaced Decima in Captain Billy in November 1891.
In 1893, Moore returned to the D'Oyly Carte organisation to create the role of Bab in the unsuccessful Jane Annie, with a libretto by J. M. Barrie and Arthur Conan Doyle and music by Ernest Ford.
The company was then sent to Australia, where she starred as Bessie Brent in the musical comedy, The Shop Girl, and later played the Prima Donna of the Ambiguity Theatre in In Town.
She starred in The White Silk Dress by A. McLean (1896) at the Prince of Wales Theatre and the British production of Lost, Strayed or Stolen (1897).
[11] She toured abroad extensively[1] and played Lucia in Great Caesar, a Victorian burlesque by George Grossmith Jr. and Paul Rubens at the Comedy Theatre, in mid-1899.
[12] She returned to the D'Oyly Carte later in 1899, for the third and last time, to play Scent of Lilies in The Rose of Persia, after which she starred in the musical comedy Florodora (1900–01) at the Lyric Theatre.
[1] In 1905, Moore remarried and accompanied her second husband, Major (later Brigadier General Sir) Frederick Gordon Guggisberg, to West Africa.
An officer in the Royal Engineers, he was appointed director of surveys and later governor and Commander-in-Chief of the Gold Coast (now Ghana) and then British Guiana.
[1] In 1908 Moore was one of the founding members of the Actresses' Franchise League, which supported the women's suffrage movement through pro-suffrage propaganda plays, readings and lectures.
In 1918 she was made a Commander of the Most Excellent Order of the British Empire for her services and was awarded the overseas medal and the Médaillon de reconnaissance.