Born on 16 May 1903 in South Brisbane, Katharine McGregor received a strict upbringing from her lawyer father. Upon completing her schooling at Brisbane Girls' Grammar School, Katharine won an open scholarship to the University of Queensland where she studied classics. She graduated with first-class honours in 1923, completed a thesis on 'The Island of Samos' for her masterate, and served as honorary secretary of the short-lived Queensland Classical Society.

Persuaded by her father to carry on the family's legal tradition, Katharine sat the sat the Barristers' Board examinations. As a barrister, she became friends with trailblazing lawyer Agnes McWhinney. Katharine joined her father's law firm where she practised as a solicitor and became a partner in the firm. Katharine set up her own firm in September 1935. From 1939, Katharine worked as a private tutor in Greek and Latin, and as an examiner in classics at secondary and tertiary levels. Softly spoken and nervous, Katharine McGregor was an avid reader. She died on 25 June 1979 in Kangaroo Point.

Sources used to compile this entry: Kenny, Catherine, 'McGregor, Katharine Elizabeth (1913-1979)', in Australian Dictionary of Biography Online, Australian National University, 2006, http://adb.anu.edu.au/biography/mcgregor-katharine-elizabeth-10962/text19483; Purdon, Susan and Rahemtula, Aladin (eds), A Woman's Place: 100 Years of Queensland Women Lawyers, Supreme Court of Queensland Library, Brisbane, 2005.