Ernst Steinsdorff studied since 1858 at the universities of Kiel, Göttingen and Berlin. In 1863 he received his doctorate in Berlin with a thesis " De Ducatus, qui dicitur Billingorum, in Saxonia origine et progressu ". Steinsdorff was secretary under the direction of Karl Friedrich Samwers and was also private secretary to the Duke Frederick VIII of Schleswig -Holstein. After his dismissal from the service of the Duke, he returned to Göttingen to the university. In 1866 he received the venia legendi to two years, in June 1868 with no time limit. In 1877 he married Clara Waitz, the youngest daughter of his teacher Georg Waitz. On June 26, 1873 Steinsdorff was extraordinary, on April 18, 1883 a full professor.
Steinsdorff is. Mainly by its 1874 and 1881 published in two volumes, based on thorough research source yearbooks of the German Empire under Henry III significant. It is the most comprehensive study to date about Henry III. He has also written several articles for the General German Biography. The last years of his life he was with the preparation of the new edition of Dahlmann - Waitz'schen source study of the German History ( 6th edition, 1894 ) were employed.
- Yearbooks of the German Empire under Henry III. 2 volumes, University Press, 1963 Darmstadt, ND from 1874 and 1881.
- De Ducatus, qui dicitur Billingorum, in Saxonia origine et progressu. Berlin 1863.