[2] She previously held the role of New South Wales Commissioner for Children and Young People between 2010 and 2013.
[2] Mitchell was born at St Margaret's Hospital, Sydney to a single mother, Florence Pianta, who had moved to Sydney from Queensland when she was discovered she was pregnant, and had changed her name by deed poll to Toni Mitchell and told staff she was pregnant to avoid questions about her marital status.
[3] She was appointed NSW Commissioner for Children and Young People in 2010, a position which she held for the following three years.
[2][4] On 25 February 2013, the Gillard government appointed Mitchell as the first National Children's Commissioner within the Australian Human Rights Commission, a role that had been flagged in the previous year to ensure that the voices of young people were heard by Government.
Her appointment, for a five-year term, was designed to "focus solely on the needs of children and their rights and their interests and the laws and policies and services that affect them".