Fabian Stumm was born on February 1, 1981 in Koblenz, Germany. From 2001 to 2003 he studied acting at the Lee Strasberg Theatre & Film Institute in New York, USA. Upon his return to Germany, he participated in stage productions at Berlin's Ballhaus Ost, the HAU - Hebbel am Ufer, the Volksbühne Berlin and the Münchner Kammerspiele, among others. He collaborated with the Israeli artist Keren Cytter in her dance and performance company D.I.E NOW, which performed at the Tate Modern in London, the Theater Neumarkt in Berlin and other theaters in Europe, Asia and the USA. Since 2008 he has also appeared in several short films by various directors.   

Fabian Stumm made his feature film debut in 2012 with a small role as a US soldier in Cate Shortland's award-winning war drama "Lore" (DE/AU/GB). This was followed by a lead role in the horror thriller "Bela Kiss: Prologue" (2013) about the Hungarian serial killer Béla Kiss.

In the following years, Stumm appeared in small and large supporting roles in television productions, including as a secretary in the social comedy "Bella Casa - Keiner zieht aus" (2014), as a patrol officer in "600 PS für zwei" (2015), and as a therapist in an episode of the series "Druck". Keren Cytter cast him in the lead role of her feature film "Middle of Beyond" (2018), which was presented at the European Media Art Festival in Osnabrück. Stumm has also acted in numerous short films. On the big screen, he played the role of a shop owner in the award-winning sisterhood story "Ivie wie Ivie" ("Precious Ivie") (2021) and a civilian police officer in the award-winning life and friendship story "Große Freiheit" ("Great Freedom", AT/DE 2021).

At the Achtung Berlin Film Festival in fall 2021, Fabian Stumm presented his directorial debut, the 17-minute short film "Bruxelles", in which he also starred alongside Anneke Kim Sarnau. His second short film "Daniel" won the award for best medium-length film at the 2022 Achtung Berlin Festival.

Stumm's first feature film as a director, the gay relationship drama "Knochen und Namen" ("Bones and Names") premiered in the Perspektive Deutsches Kino section at the Berlinale 2023, winning the Heiner Carow Prize of the DEFA Foundation. Stumm was also honored for Best Screenplay at the Neiße Film Festival. "Knochen und Namen" was released in German cinemas in January 2024.