Engelmann studied at the University of Heidelberg and at the Humboldt University of Berlin. During the revolution of 1848/49 he identified with the republican movement in Germany, and wrote for the Prussian revolutionary paper Freier Demokrat (Free Democrat) for a while in 1849. In the same year, he emigrated of necessity to the United States, where he found work on a farm in Marshall, Michigan. In 1851 he moved to Oshkosh, Wisconsin, and then to Milwaukee, where he was engaged by the Milwaukee Schulverein as principal of the German-English Academy, which he worked for until his death. In 1873 he established the first kindergarten of the academy, and instituted instruction in singing, gymnastics, and drawing, as well as helping to found the Wisconsin Natural History Society. The collection of this institution was transferred to the Milwaukee Public Museum in 1882. Engelmann was also active in several organizations of freethinkers, wrote numerous articles, and lectured before liberal and scientific societies.
- Engelmann, Peter 1823 - 1874, Wisconsin Historical Society, Madison, United States.