Günther Maria Halmer was born in Rosenheim on January 5 1943. Graduating from school, he enlisted in the German Air Force with the intention of becoming a pilot. Frustrated by the authoritarian military doctrine, he soon quit and travelled abroad for several years, working in a Parisian hotel and an asbestos mine in Canada. After returning to Germany, Halmer studied acting at the renowned Otto-Falckenberg-Schule in Munich from 1968 until 1969. Upon receiving his diploma, he got an engagement at the Münchner Kammerspiele, and until 1974, he performed regularly in plays like "Jagdszenen in Niederbayern" and "Pioniere in Ingolstadt".

From the mid-1970s on, Halmer focused on his burgeoning film and TV career. After his breakthrough with the 1974 TV miniseries "Münchner Geschichten", he made his debut in a theatrical release with a supporting role in "Die Angst ist ein zweiter Schatten" ("Fear is a Second Shadow", 1975). Halmer went on to play Israeli athlete André Spitzer in the US TV production "21 Hours at Munich" ("Die 21 Stunden von München"), a dramatized account of the 1972 terrorist attack at the Olympic Games in Munich. From 1977 until 1983, he had a recurring role in the popular TV series "Polizeiinspektion 1".

On the big screen, he played a widowed father of a teenage girl in "Lucky Star" (1979), Mahatma Gandhi's confidante Herman Kallenbach in the Oscar-winning epic "Gandhi" (US 1982) and infamous SS officer Rudolf Höß in Alan J. Pakula's "Sophie's Choice" (US 1982). Six years later, he again portrayed Höß in the miniseries "War and Remembrance" (US 1988). Alongside Maximilian Schell, Omar Sharif and Laurence Olivier, Halmer also starred in the TV production "Peter the Great" (US 1986).

In his native Germany, he had starring roles in the TV comedy "Mrs. Harris - Ein Kleid von Dior" (1982), the miniseries "Roncalli" (1986) and the psychological thriller "Operation Dead End" (1986). In 1988, Günther Maria Halmer was cast as the lead of the TV series "Anwalt Abel", which successfully ran until 2001. During that period, he also had memorable turns in "Bangkok Story" (1989), "Abrahams Gold" ("Abraham's Gold", 1990) and "Der Fall Lucona" ("The Lucona Affair", 1992). Halmer maintained a busy schedule and starred in numerous productions throughout the years, including the miniseries ""Tödliche Wahl" (1995), the rural drama "Der Weibsteufel (1999) and the comedy "Trennungsfieber" (2000).

Christian Petzold's acclaimed "Die innere Sicherheit" ("The State I Am In", 2000) marked Halmer's return to the big screen after seven years, and he subsequently played supporting roles in the theatrical releases "Der Stellvertreter" ("Amen.", DE/FR/RO 2002), "Das Herz ist ein dunkler Wald" ("The Heart Is a Dark Forest", 2007) and "Märzmelodie" ("Melodies of Spring", 2008). On TV, he was seen in "Der Tanz mit dem Teufel - Die Entführung des Richard Oetker" (2001), "Ghettokids" (2002), "Mörderherz" (2002) and the award-winning drama "Die Konferenz" (2004).

In addition to his dramatic roles, he often starred in light-hearted TV comedies like "Liebe hat Vorfahrt" (2005), "Plötzlich Opa" (2006), "Oh Tannenbaum" (2007), "Mein Nachbar, sein Dackel & ich" (2009), "Ein Drilling kommt selten allein" (2012) and "Vier Drillinge sind einer zuviel" (2014).

In 2015, Günther Maria Halmer was the male lead in Lars Kraume's "Familienfest", playing a mean-spirited patriarch who is confronted by his grown-up children on his 70th birthday. He then appeared again in a number of TV productions, such as the fairytale film "Prinzessin Maleen" (2015), the romance "Die Hochzeit meiner Eltern" (2016) and the comedy "Tief durchatmen, die Familie kommt" ("Ho Ho Ho to You", 2015) as well as its sequel "Von Erholung war nie die Rede" (2017).

A variation on his numerous roles as a grumpy husband and family patriarch Halmer gave in the award-winning feature film "Sommerhäuser" ("The Garden", 2017), about an extended family in which various conflicts arise during a summer holiday spent together. He also played a stubborn father in Sherry Hormann's "Wir lieben das Leben" (2018, TV), followed by a part as an alcoholic, but morally upright doctor of a police officer who got involved in a hit-and-run accident in the much praised thriller "Der Polizist und das Mädchen" ("One Man's Happiness", 2018, TV).

On the big screen Halmer starred in the comedy "Eine ganz heiße Nummer 2.0" (2019) and the drama "Die Vergesslichkeit der Eichhörnchen" (2020), in which he impersonated a dementia patient, who believes his nurse is his deceased wife. This film was released in the summer of 2021. Also in 2021, Halmer was awarded the Bavarian Order of Merit. 

In 2023, the year of his 80th birthday, two films starring Halmer were released: The tragicomic relationship story "Weißt du noch" ("Remember Me") with Senta Berger, and the comedy "Enkel für Fortgeschrittene", a sequel to "Enkel für Anfänger".