Baumgarten, son and grandson of pastors, studied theology in Jena in 1842, but after a year to philology and history at the University of Halle. After a politically motivated Relegation continued Baumgarten studying 1845 in Bonn continued and finished it in Göttingen. In Jena, he joined the fraternity in 1842 in the castle cellar, today's fraternity Arminia on the castle cellar, in Hall 1843, fraternity Allemannia to. After working as an editor of the German Reich Gazette (Braunschweig ) from the Revolution to 1852 Baumgarten in 1853 went to Georg Gottfried Gervinus, who had been charged with treason, to Heidelberg. He published a defense for Gervinus and worked on the history of the 19th century.
From 1855 to 1861 Baumgarten worked as a journalist and published a work on Spanish history during the time of Emperor Charles V and the history of Spain from the French Revolution to his presence. He followed in 1861 an appointment as Professor of History and Literature at the Technical University of Karlsruhe and joined in 1872 as a professor of history and literature history at the University of Strasbourg.
Baumgarten wrote in 1882 an unfinished biography of Emperor Charles V, Charles Brandi wanted to originally continue with the subsequent volumes, but decided to utter a redesign using the Baumgarten'schen biography.
As an advocate of liberalism was Baumgarten repeatedly before deciding to approach the Bismarck's ideas and to dispense with liberal ideas or consistently insist on the original liberal principles. This was followed by Baumgarten in his work The German liberalism. A self-criticism in the negative. However, he took the second band of German history in the nineteenth century by Heinrich von Treitschke as an opportunity to criticize the unilateral policy of Prussia in the German Empire. In his criticism, he complained both Treitschke poor archival work and the methodological weaknesses of his work, as well as the controversy sounding his Prussian- national historiography, which was directed in their tendency both against Austria, England, Judaism and liberalism. This sparked a fierce Baumgarten journalistic debate, in which involved well-known historian and under the name Treitschke -Baumgarten Controversy (1882 /83) is known. Baumgarten had written, inter alia, for the Historical Journal (HZ ), but left her after the HZ had decided, under the direction of Heinrich von Sybel in this historical dispute within the meaning of Treitschke and represented there positions, which included the Treitschke, for him were no longer acceptable. Baumgarten's defeat was also a defeat of German liberalism.
Baumgarten was of Sciences since 1880 a full member of the Historical Commission of the Bavarian Academy. He was a teacher of his nephew, Max Weber, as one of the founders of sociology in Germany made his name.
Hermann Baumgarten was married in 1855 to Ida Fallstein ( 1837-1899 ), the daughter of the Privy Council financial Georg Friedrich Fallstein ( 1790-1853 ). The couple had eight children, four of whom reached adulthood: Fritz (1856-1913), Otto (1858-1934), Emmy (1865-1946) and Anna ( 1868-1943 ).
- The German liberalism. A self-criticism. Berlin 1866.
- Notes to Treitschke's " German History, volume 2. Strasbourg 1883.