Deborah Jacobs, usually known as Daisy, was born in Melbourne in 1870, one of nine children of Hannah (nee Woolf) and Isaac Jacobs. Her father was, at one time, president of the St Kilda Hebrew Congregation. In commerce, he was a pioneer of the tobacco industry in Australia.
On 18 July 1888, when 18 years old, Daisy married Isaac Isaacs, a barrister-at-law. He was 32 years old at the time. Their marriage would last for 60 years, until Isaac's death in 1948. Children of the marriage were Marjorie (born 1890) and Nancy (born 1892).
Isaac Isaacs would later become chief justice of the High Court of Australia and Governor-General of Australia. He was knighted in 1932 and, after his retirement in early 1936, Sir Isaac and Lady Isaacs lived at four addresses in Victoria at South Yarra, Toorak and Macedon.
Over the years of their relationship Daisy Isaacs was, because of the offices her husband held, often left to her own devices. Sir Zelman Cowan, in a biography of Sir Isaac Isaacs, stated that Daisy developed a distinct identity as 'a woman of dignified appearance, strong personality and considerable style, who enjoyed her public position.'
Following the death of her husband in Melbourne in 1948, Lady Isaacs lived in Bowral, New South Wales, until her death in June 1960.
Colin Choat, 'Isaacs, Lady Deborah (Daisy) (1870–1960)', Obituaries Australia, National Centre of Biography, Australian National University, http://oa.anu.edu.au/obituary/isaacs-lady-deborah-daisy-14157/text25168, accessed 29 July 2015.