The Wikipedia article on Elizabeth Kenny lists notable individuals who had been polio patients of Sister Kenny. Among those listed are Alan Alda, Dinah Shore, and Rosalind Russell's nephew. It is known that Rosalind Russell had long campaigned to portray Sister Kenny on film; her nephew's treatment might have been a factor in that interest.
It was reported at the time that Elizabeth Kenny was paid $100,000 for the rights to her story by RKO. She then donated the amount to a trust fund set up for the benefit of 17 nephews who were all in the Royal Australian Air Force at the time. It was stipulated in her contract with RKO that Russell portray her in the film.
Unlike as portrayed at the beginning of the film, Kenny had no formal nursing education. She earned the title of "Sister" (rank equivalent of a 1st Lt.) during her service in the Australian Army Nursing Service during WWI. She used that title the rest of her life, which was controversial as in the British Commonwealth that title was reserved for senior qualified nurses (the equivalent of a Registered Nurse in the USA).
This film did poorly at the box office for RKO, resulting in a loss of $660,000 ($8.9M in 2017) according to studio records; it even did poorly in Australia.
Final film of Philip Merivale, who died before the film's release. He played the orthopedic surgeon Dr. Brack.