Daughter of (Dr) Frederick Reginald Edward Duke and Eva Reeves, née Collins.
Diane Alley was educated at Clarendon Presbyterian Ladies' College Ballarat, Victoria, Methodist Ladies' College Melbourne and Girton Church of England Girls' Grammar School Bendigo. She completed her tertiary education at the University of Melbourne where she gained a BA Honours in 1948. She later completed a Diploma of Criminology in 1976.

She married (Mr Justice) Stephen George Alley in 1949 and had four children; two sons and two daughters.

Apart from rearing her children, she has devoted her life to working for equality for women and social justice for all. She held the position of president of the National Council of Women of Victoria from 1977-1980. She was convenor of Family Policy Sub-committee Victorian Consultative Council of Social Development from 1979 and member of the Fairlea Women's Prison Council. She was a member of the Victorian Premier's Equal Opportunity Advisory Council in 1978 and chair, National Status of Women Committee, United Nations Association of Australia (UNAA) from 1980. She has been an honorary magistrate of the Children's Court from 1972. She has travelled overseas to represent the National Council of Women (NCW) at conferences of the International Council of Women. From 1986-1994, she held the position of international convenor of the Child and Family Standing Committee of the International Council of Women. In 1993 Diane Alley received a testimonial from the United Nations Co-ordinator for the International Year the Family (IYF), designating her an IYF patron for exemplary support to the UN program on IYF. On her retirement from the Board of the Children's Protection Society in 1999, she was made a life vice-president, only the second since its formation in 1896.