His research on the ancient world used a comparative method, drawing on a variety of ethnological material for the study of social and religious matters.

[2] He was influential most of all through his work on the formation of religious concepts, which influenced thinkers such as Albrecht Dieterich, Ludwig Radermacher, Aby Warburg, Walter F. Otto, and Ernst Cassirer.

Other students included Hermann Diels,[8] Paul Natorp,[9] Hans Lietzmann,[10] Albrecht Dieterich, Richard Reitzenstein,[11] and Aby Warburg.

[12] Ulrich von Wilamowitz-Moellendorff, the leading German classical scholar of the following generation, studied at Bonn 1867-9; but tended to disagree with Usener.

His works include: Hermann Usener's parents were Georg Friedrich Usener (20 August 1789–15 April 1854), Landesoberschultheiß in the Amt of Weilburg and his wife Charlotte Henriette Caroline Vogler (1798–1855), daughter of Georg Vogler, a physician and member of the Princedom of Nassau's medical council.