Elizabeth Diggory was educated at two girls' day schools in the UK and Westfield College, University of London where she took an Honours degree in History in 1967. Following teacher training and a PGCE at Cambridge, she began her teaching career at the King Edward VI High School for Girls in Birmingham. In 1983, she was appointed head of St Albans High School for Girls and Manchester High School for Girls in 1994. She was appointed High Mistress of St Paul's Girls' School in 1998.

A member and former President of the Girls' School Association, she has had a lifelong interest in the education of girls. She has chaired the GSA's Professional Development Committee and contributed to courses of professional development for staff and heads. She has taken part in several school inspections and is a governor of three independent schools in England and the English College in Prague. She was appointed by the Secretary of State for Education as a member of the General Teaching Council for England (2000-2002) and is a Trustee of the HSBC Education Trust.