[4] Seymour began in song and dance routines at a very young age and would go on to appear in a string of highly successful long-running musicals staged at London's Gaiety Theatre during the 1890s.

[3][6] She first appeared on stage in 1875 as a member of Mr. Chatterton's Children's Pantomime Company,[6] and the following year, billed as, "the Little Wonder", six-year-old Seymour sang and danced a version of the hornpipe on 13 March at The Town Hall, London.

[20] Seymour made her debut at the Gaiety Theatre on 31 September 1891 as a dancer in Joan of Arc an opéra bouffe by John L. Shine, Adrian Ross and composer Frank Osmond Carr.

[22][23] Seymour stayed with Black Eyed Susan through June, after which she assumed the role of Fettalana to Letty Lind's Cinder-Ellen and Sylvia Grey's Linconsina for the last few performances at the Grand Theatre of the popular burlesque comedy, Cinder Ellen up too Late.

[24][25] Over the summer and early fall of 1892 Seymour toured with Cinder-Ellen up too Late and remained with the show when it reappeared at the Gaiety Theatre at the beginning of October for a run that would continue until mid-December.

[25][26][27] After an eight-month run in Round the Town, Seymour returned to the Gaiety Theatre on 9 September 1893, where she would remain until 1901, to appear in Edwardes' revival of Audran's comic opera La Mascotte,[28] and on 21 October, Don Juan, a burlesque by James T. Tanner, with lyrics and music by Adrian Ross and Meyer Lutz, respectively.

[30] Don Juan closed at the end of June 1894 and was followed that November with Seymour in the role of Miss Robinson, a fitter with the Royal Store, in The Shop Girl, a musical comedy H. J. W. Dam and Adrian Ross.

[33] Counter to George Edwardes' advice, Seymour chose to leave the Gaiety to share top billing with James E. Sullivan in a revival of The Casino Girl[34] that was produced at the Knickerbocker Theatre, Broadway on 8 April 1901.

[35] The Casino Girl ran until 11 May after which, toward the end of June, she was engaged at the Knickerbocker as a feature dancer in The Strollers, a musical comedy by Harry B. Smith and Ludwig Englander that starred Francis Wilson.

She was stopped on Fifth Avenue, not far from Central Park, for driving at an excessive speed and escorted to a nearby police station where she was assigned a court date and required to pay a modest deposit to encourage her attendance.