Louise Maria Hubertine Heynen, born on 22 February 1862 in Cologne near Neumarkt, was the second of eleven or twelve siblings.

In 1898 Dumont left Stuttgart in order to join the Deutsches Theatre in Berlin, where she achieved her greatest successes, especially as a performer of pieces by Henrik Ibsen.

They separated in the 1920s, after which Dumont was attached to a number of young actresses, including Fita Benkhoff, Hanni Hoessrich and Luise Rainer.

She exerted less of a mimic-erotic fascination than a strong, convincing and defining gravity, which she understood as performing faithful service to the words of the author.

Her husband donated in her memory a necklace with a pearl-encircled topas that she had received as a present from Queen Charlotte of Württemberg, to be awarded to outstanding actresses during their lifetime.