The title alludes to the popular 1925 song I Lost My Heart in Heidelberg composed by Fred Raymond with lyrics by Fritz Löhner-Beda and Ernst Neubach. The film taps into the nostalgic reputation of Old Heidelberg.
| Actor | Role |
|---|---|
| EEmil HöferPastor Schönhoff | Pastor Schönhoff |
| GGertrud de LalskySophie | Sophie |
 Werner FuettererRudolf | Rudolf |
 Mary ParkerCharolotte | Charolotte |
 Sylvester BauriedlFritz Merkelbach | Fritz Merkelbach |
 Harry HalmAlex Winkler | Alex Winkler |
 Karl PlatenGeorg Schröder | Georg Schröder |
 Dorothea WieckKlärchen | Klärchen |
| VViktor GehringEngineer Frank | Engineer Frank |
| CCarla FärberTrude | Trude |
| II.W. LautschBornschläger | Bornschläger |
| MMaria MeyerhoferNot listed | Not listed |
 Josef EichheimMaster tailor Stenglein | Master tailor Stenglein |
| EElse KündingerNot listed | Not listed |
| FFrau Heuberger-SchönemannNot listed | Not listed |
| GGeorg IrmerFritz Merkelbach | Fritz Merkelbach |