Nico Birnbaum was born in Kiel. Although being an actor from the north of Germany, he frequently gravitated towards the more sunnier south of Europe. He thus studied literature and philosophy in Aix-en-Provence in France, wrote part of his thesis on Franz Kafka in Florence and also lived in Rome where he worked as a translator and German teacher.

He gained his first professional acting experience at the Florentine film school Scuola Nazionale die Cinema Indipendente. Here he acted in a number of short films and took part in his first feature film Reality News by Salvatore Vitiello. After accomplishing his PhD with summa cum laude in 2013, he gave up his academic career in favor of pursuing his dream of becoming a professional actor. He has since played supporting roles in several German TV-series such as Heldt, Die Spezialisten - Im Namen der Opfer or SOKO Wismar. He further took part among others in Babylon Berlin or Auris - Die Frequenz des Todes, he played the lead as a drag queen in Nihat - Alles auf Anfang and had another leading part in the feature film Furioso alongside Jan Josef Liefers and Katharina Thalbach. Nico Birnbaum portrayed the role Alexis von Roenne in the Hollywood movie Operation Mincemeat by John Madden and he was working with Thomas Kail in the historical miniseries We Were The Lucky Ones alongside Logan Lerman and Joey King. The series premiered in March 28th 2024 on hulu.
In 2024 Nico Birnbaum played a leading role in the Egyptian feature film Crows alongside Amr Saad, he appeared in the Spanish Miniseries Ena - La Reina Victoria Eugenia by Estel Díaz and alongside James McAvoy in Control by Robert Schwentke.