He retired from the Bavarian civil service soon after the referendary and began publishing his songs and ballads (Lieder und Balladen) in Emanuel Geibel's Münchener Dichterbuch (1862); he was soon inducted into the Munich circle of writers known as Die Krokodile.
By the age of 25 he had earned a reputation as a gifted romantic with his lyrical poems (especially the powerful ballad of the Sendlinger Bauernschlacht, one of the highlights of his career) and the humorous peasant novel Der alte Praktikant.
He also gained importance as a leading figure of the Verband Alter Corpsstudenten (VAC), founded in 1888 and chaired by Hopfen from 1895 until his death.
Soon after taking office, he submitted the plan for a monument dedicated to the German Student Corps at the Rudelsburg to Prince Otto von Bismarck.
1892); Arge Si/ten (1869); Der graue Freund (1874, 2nd ed., 1876); and Verfehite Liebe (1876, 2nd ed., 1879) are attractive, while of his shorter stories Tiroler Geschichten (1884–1885) command most favour.