Brentano received his Ph.D. in economics in 1867 from the University of Göttingen and was professor of political theory from 1871 to 1931, successively, at the Universities of Berlin, Breslau, Strassburg, Vienna, Leipzig, and Munich.

In 1868 Brentano made a thorough study of trade unionism in England that resulted in his Die Arbeitergilden der Gegenwart (1871–72; “Workers' Guilds of the Present”). In it he argued that modern trade unions were the successors of the medieval guilds. The book soon became an authoritative source on industrial-era work associations. His other works, which are of a more theoretical nature, relate chiefly to political economy.

Brentano ardently opposed the rise of German militarism and was for many years an outspoken pacifist in Germany. He remained a strong advocate of trade unions.