Gabriela Helena Anna Dohm was born in Salzburg, Austria, on September 23, 1943, the daughter of actors Will Dohm and Heli Finkenzeller. After graduating from the School of the Sisters of the Sacred Heart in Berlin, Gaby Dohm planned to attend the drawing class at the Berlin Academy and then work as a children's book illustrator. However, this plan did not come to fruition because, according to the academy's strict statutes, she was too young to study.

Instead, Dohm tried her hand at acting: playing Franziska in Lessing's "Minna von Barnhelm," she auditioned for the famous acting teacher Elsa Bongers and, to her own surprise, was immediately accepted as a student. When Dohm wanted to join the Otto-Falckenberg-Schule in Munich in 1962, the director at the time, Gerd Brüdern, rejected her on the grounds that her acting had already matured. It was not until 1996, after more than 30 years of stage, television and film work, that Dohm was to take further acting lessons in New York.

After her first, mostly smaller appearances at the Düsseldorf Schauspielhaus, Dohm went to the Munich Residenztheater in 1966, where she soon had her breakthrough. She was a member of the theater's ensemble for about twenty years, appearing in both classical and modern plays.

Gaby Dohm made her television debut in 1964 with a supporting role in "Meine Nichte Susanne". The following year she had her first supporting role in Axel von Ambesser's Wilhelm Busch adaptation "Die fromme Helene". Until the mid-1980s, however, she only appeared sporadically in television productions such as Falk Harnack's "Ein Fall für Herrn Schmidt" (1971) and the crime series "Butler Parker" (1973). She appeared even more rarely in movie productions: Dohm was part of the ensemble in the comedy "Als Mutter streikte" ("When Mother Went on Strike", 1974) and played the mother of the main character in Franz Seitz's Thomas Mann adaptation "Doktor Faustus" (1982).

Gaby Dohm worked several times with the famous Swedish director Ingmar Bergman, who lived mainly in Munich between 1976 and 1985 after leaving his homeland because of a tax case. He first cast Dohm in a small role as a "woman with a child" in the feature film "The Serpent's Egg" (DE/US 1977) and gave her a leading role in his German television production "Aus dem Leben der Marionetten" ("From the Life of Marionettes", 1980). Bergman also repeatedly cast Dohm in his stage productions at the Munich Residenztheater: a supporting role in "Tartuffe" (1979) was followed by the celebrated title role in "Yvonne, Princess of Burgundy", (1980); Dohm received the Munich Audience Award for her leading role in "Scenes from a Marriage", (1982).

Gaby Dohm became known to a wide audience in 1984 through the television series "Die Wiesingers", in which she played the mother of the titular family. Her big breakthrough came shortly thereafter in the ZDF series "Schwarzwaldklinik" ("The Black Forrest Hospital"), which began in 1985. With ratings of over 80 percent at times, the series starring Dohm as Christa Brinkmann, nurse, later doctor and wife of the head physician played by Klausjürgen Wussow, became a television classic. This role, which she played until the end of the popular series in 1989, brought her (as well as the rest of the regular cast) unprecedented popularity, also internationally: in 1985 she received the Italian Television Award for the role. The sudden success of the series probably contributed to Dohm's decision to leave the Residenztheater and concentrate on her television career.

In the following years she took part in a huge number of TV productions, mainly in series and serials. She played a leading role as a widowed countess in the series "Donauprinzessin" (1993), a police psychologist in the Nuremberg episodes of "Polizeiruf 110" (1997-2000) and an amateur detective in the first season of "Vier Frauen und ein Todesfall" (2005-2007). On the big screen, she made only small appearances as a plastic surgeon in Helmut Dietl's "Late Show" and as a baroness in Margarethe von Trotta's "Rosenstraße" (2003).

In 2011, Dohm replaced actress Rosel Zech, who died shortly thereafter, in the ARD series "Um Himmels Willen": Dohm took on the role of nun and later Mother Superior Louise von Beilheim, which was initially planned for just a few episodes, but then became a regular part. Over the decades, Gaby Dohm played small and large guest roles in "Der Alte", "Derrick", "Ein Fall für Zwei", "Rosamunde Pilcher", "Das Traumhotel" and "Das Traumschiff"("The Dream Ship") - sometimes several times. In television films, she played leading roles in the disaster film "Die Sturmflut" (2006), in Christian Wagner's homeland drama "Hopfensommer" (2011), in the acclaimed Christmas comedy "Alle unter einer Tanne" (2014) and as a dementia patient in the melodrama "Marie räumt auf" (2016). She was nominated for the German Acting Award for her portrayal of a critical mother-in-law in the family comedy "Tanze Tango mit mir" (2021).

Gaby Dohm, who has appeared in well over 100 television productions, was married to cameraman Adalbert Plica in her first marriage, from which her son Julia Plica, a television director, emerged. Since 1994, she has been in a relationship with television director Peter Deutsch, with whom she has also worked several times, most recently on the romance "1000 Meilen für die Liebe" ("1000 Miles for Love", 2001). The couple lives in Munich.