Carla is the sister of Ansgar (Wolfram Grandezka) and the half-sister of Leonard (Lars Korten), Sarah Hofmann (Sina-Valeska Jung), Nico (Verena Zimmermann) and Constantin (Milan Marcus). She was married to Bernd von Beyenbach (Ron Holzschuh), but this was purely a marriage of convenience that Carla concluded to conceal from her father Johannes (Thomas Gumpert) that she was a lesbian. Carla is currently married to Susanne Brander (Claudia Scarpatetti), but they have filed for divorce.
Carla is the oldest daughter of Johannes von Lahnstein, an aristocrat. She is a smart businesswoman and very sure of herself. Carla is a lesbian, but kept this a secret for a long time. Only her younger brother, Leonard, knew it all along. When Carla met Hanna Novak (Katharina Dalichau), she very quickly fell in love with her. However, Hanna was straight and in a relationship with Lars Schneider (Herbert Ulrich), who had split up with Hanna's sister to be with her. Carla and Hanna eventually developed a romance and Hanna ended her relationship with Lars, but died of a stroke after a kidney failure a few months later.
Following a brief and disastrous relationship with Anke, a woman Carla met in a bar and later found propositioning her stepdaughter (Bernd's daughter), Carla met Susanne Brandner, who was recently divorced from her husband and who had moved back to her hometown from Buenos Aires. Susanne had an adopted son Paul and also had custody of her stepdaughter, but longed for another child. In late 2006, Carla and Susanne marry and decided to have a baby together. Susanne decided she wanted Lars Schneider to be the father for their child and that she would carry the baby, but was heartbroken to discover she was infertile. Carla agreed to bear the baby and after some initial hesitation, bearing in mind her past history with Lars, Lars was settled upon as the baby's father. Being pregnant, Carla went to work in New York. In March 2007 she returned for her brother Ansgar's marriage to her best friend Nathalie Käppler (Jenny Winkler).