We do know that Karen Marie was born out of wedlock, possibly from prostitution, that she wrote to Andersen a few times in her life and, as he deliberately does not mention her in any of his three autobiographies, was apparently a source of some shame to him. This may have been because he was determined to move into the upper classes, while she remained a poor washerwoman.

Another detail from Andersen's life would seem to have inspired The Red Shoes: Andersen's father was a shoemaker. He recalls an incident from his childhood when a wealthy woman sent his father a piece of expensive red silk to make a pair of dancing shoes for her daughter. He worked tirelessly on the shoes, combining the silk with some red leather of his own, but when the woman came for them, she was critical, saying that he had done nothing but spoil her silk. Andersen's father said that he might as well spoil his leather as well, and cut up the shoes in front of her.

Finally, the background of Karen's miserable poverty, the pitfalls of sudden fortune and the delights and pains of pursuing art (in Karen's case, dance) can be seen to reflect Andersen's life story. He grew up in abject poverty, but was determined to work his way up in society as an artist. In his early years, he struggled constantly for money, dependent on wealthy patrons. Even when he had achieved European acclaim, he wrote much about the fear of the past coming back, and of everything had achieved being taken away again.