In 1830 he brought out what was a complete novelty in Danish literature, a comedy in rhymed verse, Amors Genistreger (Cupid's Strokes of Genius).

[1] In the same year Hertz published anonymously Gjengangerbrevene (Letters from a Ghost), which he pretended were written by Jens Immanuel Baggesen, who had died in 1826.

The book was written in defence of Johan Ludvig Heiberg, and was full of satirical humour and fine critical insight.

Hertz passed through Germany and Switzerland into Italy in 1833; he spent the winter there, and returned the following autumn through France to Denmark.

To this succeeded the tragedy of Ninon in 1848, the romantic comedy of Tonietta in 1849, Et Offer (A Sacrifice) in 1853, and Den yngste (The Youngest) in 1854.

He has bequeathed to the Danish theatre, in Svend Dyrings Huus and King René's Datter, two pieces which have become classic.