Born in East Melbourne, Victoria, Australia, into a prosperous family that later fell on hard times, Ethel Florence (who preferred to answer to Et, Ettie or Etta) was the elder daughter of Walter Lindesay Richardson MD (c. 1826–1879) and his wife Mary (née Bailey).

In 1894 in Munich Richardson married the Scot John George Robertson, whom she had met in Leipzig where he was studying German literature and who later briefly taught at the University of Strasburg, where his wife became ladies' tennis champion.

At the Presbyterian Ladies' College, she fell in love with an older schoolgirl; the feelings of adolescent females awakening to their sexuality were reflected in The Getting of Wisdom.

Her friend Olga Roncoroni, who had lived in the Robertson household for many years, filled the gap left by the death of her husband.

[2] The Fortunes of Richard Mahony is Richardson's famous trilogy about the slow decline, owing to character flaws and an unnamed brain disease, of a successful Australian physician and businessman and the emotional/financial effect on his family.

[2] Richardson also produced a single volume of short stories and an autobiography that greatly illuminates the settings of her novels, although her Australian Dictionary of Biography entry doubts that it is reliable.

[7] Lillian Richardson, Ethel's younger sister, married A. S. Neill after divorcing her first husband, and helped found and run Summerhill School.

[11] The Getting of Wisdom was filmed in 1977, directed by Bruce Beresford, from a screenplay by Eleanor Witcombe, starring Susannah Fowle as "Laura Rambotham" with supporting roles by Julia Blake, Terence Donovan and Kerry Armstrong.