She is a core-member and General Manager for Guerilla Opera, whose production of Vores' No Exit "rocked the local opera scene" (The Phoenix) and was described by Richard Dyer as "a signature event of the city's 2007–2008 season." She has premiered three operatic roles with the company, and will premier three more by the end of the 2009–2010 season. She is a core-member of The Ludovico Ensemble with which she has performed contemporary works from composers such as: Rudolf Rojahn, Jonathan Harvey, Harrison Birtwistle, and various others; and has performed three consecutive years in The Boston Conservatory New Music Festival featuring Webern's Op. 14 Six Songs on Poems of George Trakl for soprano and chamber ensemble, Berio's Sequenza III for solo voice, and Kurtág's Kafka Fragments for soprano and violin.

Ms. de la Guardia also has acting training for stage and screen and is a member of the company of actors for The Boston Stage Company.

Current projects include: recording 12 Songs of Poems of John Donne, by Jan Kennard; singing the title role of Guerilla Opera's next production, Rumpelstiltskin, by Marti Epstein; the third season of Guerilla Opera; the seventh season of The Ludovico Ensemble; and the second season of the Boston Stage Company.