Born John Cummings, Katherine Cummings underwent gender re-assignment surgery in 1989. Prior to that, she had been married and raised three daughters. Her autobiography, Katherine's Diary : The Story of a Transsexual, was published in 1992, and her essay 'The Life and Loves of an XY Woman' in No Thanks or Regrets (1996) continues the story of her life.
Cummings grew up in the Gilbert Islands, Fiji, New Zealand, Scotland and Australia. She graduated from the University of Sydney, and after gaining a post-graduate degree in Librarianship from the University of Toronto she worked at the University of New South Wales as Reader Services Librarian. She then emigrated to America and was Reader Services Librarian at the State Library of Oregon and later, Director of Upsala College, East Orange, NJ.
Returning to Australia she worked at the University of Queensland as Deputy Librarian and then at the Sydney College of the Arts before commencing work at Macquarie University as Reference and Research Librarian.
Since then she has completed a Desktop Publishing Diploma at the Sydney Institute (TAFE) and has worked for the Australian Business Index, the Social Policy Research Centre at the University of NSW, and the Sydney Gender Centre in Petersham. She was commissioned by the NSW Attorney-General to write a report on violence against the transgendered in 2003-2004.