Gerdi Troskie completed her BMus and MMus degrees at the University of Port Elizabeth, South Africa, and continued with post-graduate organ studies at the Amsterdam Conservatorium with the early music specialist Jacques van Oortmerssen (1993-1996). She was awarded the Conservatorium's Soloist's Diploma (organ) in 1996.

In 1996, on the completion of her studies, Gerdi moved to the UK. She taught organ and musicianship at the Royal College of Music Junior Department from 1998-2005. Gerdi held the appointment of Organist and Director of Music at St Anselm & St Cecilia Roman Catholic Church, Holbom, London, from 1996-2002 and started teaching organ and theoretical studies for St Giles International Organ School in 2000. She is currently an accredited teacher at the Royal College of Organists with a teaching practice based in Worcester. Gerdi was appointed School Organist at Bromsgrove School in 2022 and she also holds teaching posts (organ and piano) at Bromsgrove School and The King's School, Worcester.

She has participated as tutor on several residential organ courses, including the annual RCO Summer Course in London, COfO courses for Young Organists and the RCO TOSE (The Organ Scholar Experience) Course in Oxford.

Gerdi has played recitals in the UK, The Netherlands, Scandinavia and South Africa.