Dähnhardt was born on 1 June 1818 in Gadebusch, now Mecklenburg-Western Pomerania, Germany. She was the daughter of the apothecary Helmuth Ludwig Dähnhardt and his wife Maria (née Brünger). Her family was from a bourgeois background and she enjoyed a good education in her youth. Early in her life her father died and she inherited a small fortune of 10,000 thalers.
No later than in 1838 she moved to Berlin against the will of her family, where she associated at Hippel's wine bar with Die Freien which is probably where she met her future husband Max Stirner. During her time in Berlin she used to, in contrast to her bourgeois and well-mannered upbringing, smoke cigars, play billiards, drink the Munich beer and dress in male attire in order to visit brothels.
She was married to the philosopher Max Stirner from 1843 to 1846. After divorcing she moved to London, where she worked as a teacher under the protection of Lady Bunsen, the wife of the Prussian embassador. Later in 1852 or 1853 she emigrated to Melbourne, Australia where she made a living as a washerwoman. After returning to England, she joined a Catholic commune, where she was found by Stirner's biographer John Henry Mackay, but refused to talk about her ex-husband and claimed, "Stirner was a very sly man whom she had neither respected nor loved, and claiming that their relationship together had been more of a cohabitation than a marriage". She died in the beginning of 1902 in London.
- Mackay, John Henry (2005). Max Stirner : his life and his work. Peremptory Publications. OCLC 268661593.
- Carus, Paul (1911). "Max Stirner, the Predecessor of Nietzsche". Monist. 21 (3): 376–397. doi:10.5840/monist19112137. ISSN 0026-9662.
- David, Sprengel (1902-11-20). "En individualist från 1840-talet". Svenska Dagbladet (in Swedish). p. 5. Retrieved 2022-02-05.
- Max Stirner (Stanford Encyclopedia of Philosophy)
- Special issue "Meinem Liebchen Marie Dähnhardt" of the German journal Der Einzige. Vierteljahresschrift des Max-Stirner-Archivs Leipzig, nr. 33/34 (February/May 2006).