Gillian Ansell, born in Auckland, made her concerto debut as a violinist with the Auckland Philharmonia at the age of 16. At 19, an Associated Board Scholarship took her to the Royal College of Music in London for 3 years to study violin, viola and piano. She then won a German Academic Exchange (DAAD) scholarship for further study in Germany at the Musikhochschule Cologne with Igor Ozim and the Amadeus Quartet.
​After working professionally in London for three years she returned to New Zealand to become a founding member of the New Zealand String Quartet in 1987. She was second violinist for two years before taking up the position of violist of the group.

​In 2001 she became Artistic Director, with fellow quartet member Helene Pohl, of the Adam New Zealand Chamber Music Festival.

​In 2008 she was made a Member of the New Zealand Order of Merit (MNZM) for her outstanding services to music in New Zealand.

​She served on the jury of the Banff International String Quartet Competition in 2019.
​Gillian plays on a 1619 Nicolò Amati viola, generously loaned by the Adam Foundation.