Rosalind Russell appears in this movie alongside Gypsy Rose Lee, whose real-life mother Russell portrayed in her most previous movie role, that of Rose Hovick in Gypsy.
According to Rosalind Russell, she and Hayley Mills did not get along during filming. She claimed that every time she turned around or walked away from Mills, she would stick her tongue out at her.
All of the old ladies at the Christmas party at the old age home are wearing purple, which is the liturgical color for the Advent season in the Catholic calendar.
Producer William Frye personally offered his friend Greta Garbo $1 million to play the Mother Superior in the film. When she declined, he offered the role to Rosalind Russell at a much lower salary.
The exterior shots were filmed at St. Mary's Home, an orphanage, in Ambler, Pennsylvania. The main building looks like a stone castle and is still standing. It was featured prominently in the film but all the interior shots were done in a studio in California.
The first feature film to be directed by Ida Lupino since The Hitch-Hiker and The Bigamist over a decade earlier.
Upon arriving at St. Francis', Mary uses the alias "Kim Novak". Rosalind Russell, who plays Mother Superior, starred with Kim Novak in Picnic.