Marcus O. Rosenmüller, born on February 27, 1963, in Duisburg, began directing his first commercial and promotional films while studying communication sciences in Munich. In 1991, he co-founded MME Film and TV Production with Jörg Hoppe and Christoph Post, directing numerous music videos through 1999, including those for Udo Lindenberg, Jule Neigel, and the band Extrabreit. 

His debut feature film was the comedy "Der tote Taucher im Wald" ("The Dead Diver in the Woods", 2000), starring Dieter Pfaff. The following year, he partnered with actor Bruno Eyron and Werner Heinz to establish Casascania Filmproduktion. Rosenmüller then transitioned to television, directing many TV series and films, often working from his own scripts. His notable projects include the drama "Die Mandantin" (2005, starring Barbara Rudnik), the thriller "Augenzeugin" (2008, also with Rudnik), and the historical drama "Gottes mächtige Dienerin" ("God's Mighty Servant", 2011), featuring Christine Neubauer as Sister Pascalina, a trusted confidante of the Pope. 

In 2011, Rosenmüller made his return to the big screen with the drama "Wunderkinder," which tells the story of two Jewish girls hiding with their families from the Nazis in 1941 Ukraine. The film premiered in German cinemas in early autumn of 2011 and earned awards for Best Film at the Giffoni Film Festival (Italy) and the Jerusalem Film Festival (Israel). 

Over the following years, Rosenmüller continued to direct numerous TV productions (often credited as Markus Rosenmüller), including the psychological drama "Am Ende der Lüge" (2013) and several successful episodes of the series "Der Taunuskrimi" (2014-2018). In 2019, he directed the docudrama "Die Affäre Borgward," starring Thomas Thieme, which explored the collapse of the Carl F. W. Borgward GmbH automobile company in Bremen in 1961. The film received the German Economic Film Award in the category "Economy Well Explained." 

Rosenmüller also directed the thriller "Flucht durchs Höllental" (2019) and its sequel "Der Feind meines Feindes" (2022), along with episodes of the crime series "Schwarzwaldkrimi" (2019, 2021) and "Ostfrieslandkrimi" (2023). 

At the Munich Film Festival in 2024, Marcus O. Rosenmüller premiered his first feature film in 13 years: "Münter & Kandinsky" (DE/CH), which explores the increasingly toxic relationship between painter Gabriele Münter and Russian artist Wassily Kandinsky. The film was released in German cinemas in October 2024.