| Name | Character | Episodes |
|---|---|---|
| Arnd Klawitter | Holger Klein | 62 |
| Ingrid van Bergen | Berta Völker | 4 |
| Jochen Busse | Prof. Hugo Schäfer | 3 |
| Oliver Stokowski | Wolf Berger | 2 |
| Hartmut Becker | Benno Schneider | 2 |
| Anica Dobra | Vera Berger | 2 |
| Julia Stinshoff | Constanze Bernardi | 2 |
| Rainer Sellien | David Schlüter | 2 |
| Sven Martinek | Veit Pauly | 1 |
| Christian Oliver | Johannes Zeller | 1 |
| Elena Uhlig | Helen Pauly | 1 |
| Johanna Klante | Theresa Stein | 1 |
| Sunnyi Melles | Nadja Pirsch | 1 |
| Katja Studt | Christina Walter | 1 |
| Wilfried Hochholdinger | Hauke Schilling | 1 |
| Antonio Wannek | Hans Schmidt | 1 |
| Marion Kracht | Dr. Sybille Vetter | 1 |
| Daniela Schulz | Luise Taller | 1 |
| Aleksandar Jovanović | Hans Pilgrim | 1 |
| Julia Brendler | Katja Kaiser | 1 |
| Marie Zielcke | Dörte Kallhammer | 1 |
| Philippe Brenninkmeyer | Henry von Helmecke | 1 |
| Jochen Busse | 1 | |
| Albert Fortell | Prof. Rainer Bernardi | 1 |
| Hansa Czypionka | Prof. Dr. Robert Schick | 1 |
| Markus Knüfken | Johannes Gärtner | 1 |
| Sarah Alles | Monika Gerlach | 1 |
| Anne Kanis | Sabine Pollack | 1 |
| Patrick von Blume | Harald Wiedemann | 1 |
| Janette Rauch | Sonja Behrens | 1 |
| Tim Morten Uhlenbrock | Alexander Urban | 1 |
| Andreas Guenther | Christian Kallhammer | 1 |