Knut Berger, born 1975 in Gelsenkirchen, studied acting at the Berlin University of the Arts (UdK) from 1999 to 2003. After graduating, he worked as a freelance actor in numerous, often experimental theater productions. These included performances in productions by choreographer Constanza Macras and Israeli director Yael Ronen, which took him to venues such as the Berlin Schaubühne, Tel Aviv, Stockholm and Thessaloniki.

He has also had engagements at Berlin's Volksbühne, Vienna's Schauspielhaus, Berlin's HAU - Hebbel am Ufer and the Ballhaus Naunynstraße. In addition to his extensive stage work, Berger took on roles in film productions while still a student. One of his first significant film appearances was in the award-winning ensemble film "Wir" (2003), where he portrayed a bisexual young man. Shortly thereafter, he starred in Eytan Fox's Israeli film "Walk on Water" (2004), portraying the gay grandson of a fugitive former Nazi. He has had smaller roles, such as an anti-globalization activist in "Die fetten Jahre sind vorbei" ("The Edukators", 2003) and a policeman in "Jerichow" (2008). In Matthias Glasner's pedophilia drama "This Is Love" (2009), he played the male part of an unlikable yuppie couple alongside Margarita Broich. He has also appeared in numerous short films and occasional television productions.

Berger's main field of activity remained the theater. Between 2012 and 2015 he appeared in two plays by Yael Ronen at the Schauspielhaus Graz, "Hakoah Wien" and "Niemandsland". Also under Ronen's direction, he appeared at the Maxim Gorki Theater in the 2013/14 season in "Der Russe ist einer, der Birken liebt" and reprised his role in that play in the 2015/16 season at the same theater. Until 2020, he regularly took on engagements at the Maxim Gorki Theater, working with directors such as Yael Ronen and Falk Richter.

At the same time, from 2013, Knut Berger increasingly took on roles in television and film again. He played supporting roles in "DORA oder die sexuellen Neurosen unserer Eltern" ("Dora or the Sexual Neuroses of Our Parents", 2015), the culture clash comedy "Marry Me!" (2015) and in "Der Geburtstag" ("Many Happy Returns"). In the "Tatort" episode "Der hundertste Affe" (2016), he had a supporting role as the manager of a biotechnology company, and in the TV romantic comedy "Liebe ist unberechenbar" (2020), he portrayed a university official who has an affair with a student.

In addition, Berger had a number of guest roles in television series, including the hospital series "In aller Freundschaft - Die jungen Ärzte," the crime series "Letzte Spur Berlin" and episodes of various SOKO crime formats. His roles ranged from lawyers and doctors to social workers and desperate fathers.

In February 2021, Knut Berger came out publicly as part of the #actout initiative in SZ-Magazin along with 185 other lesbian, gay, bisexual, queer, non-binary and trans* actors.

In the year 2022 he was seen in several award-winning productions: as a father in the ensemble of the social satire "Wir könnten genauso gut tot sein" ("We Might As Well Be Dead"), in a supporting role in the comedy series "Hell" and as a hospital doctor in Esther Gronenborn's TV thriller "Das weiße Schweigen".

Knut Berger played a leading role in the feature film "Knochen und Namen" ("Bones and Names", 2023), directed by and starring Fabian Stumm. The tragicomic story about the relationship of a gay artist couple in Berlin, stagnating in routine, was awarded at the Berlinale 2023 and premiered in theaters in January 2024.