Upon completing the Doctor of Musical Arts degree with a perfect 4.0 grade point average, McGuire was selected by competitive audition as the first woman conductor and artistic director of the 200-voice San Francisco Gay Men's Chorus, which she then led for more than a decade. In 2005 she also became the principal conductor of the Oakland-based Community Women's Orchestra. Both organisations awarded her with the honorary title "Conductor Laureate" when she returned to Australia in 2013. Inspired by the work of Jonathon Welchin Australia, in 2010 she founded Singers of the Street (SOS), a choir of people affected by or at risk of homelessness in San Francisco. She continued similar work in Melbourne with the School of Hard Knocks (2013 - 2017), with the Purple Cloak's Playing Our Part choir (2018) and musical theatre projects at Australian Catholic University: Kaleidoscope (June 2018) and Night of Broken Glass (November 2018) working alongside Warren Wills.