Eugen Bertolt Friedrich Brecht was a German poet, playwright, and theatre director of the 20th century. He made contributions to dramaturgy and theatrical production, the latter through the tours undertaken by the Berliner Ensemble – the post-war theatre company operated by Brecht and his wife, long-time collaborator and actress Helene Weigel.

Eugen Berthold Friedrich Brecht (as a child known as Eugen) was born in February 1898 in Augsburg, Bavaria, the son of Berthold Friedrich Brecht (1869–1939) and his wife Sophie, née Brezing (1871–1920). The modest house where he was born is today preserved as a Brecht Museum. His father worked for a paper mill, becoming its managing director in 1914. Brecht's home life was comfortably middle class. At school in Augsburg he met Caspar Neher, with whom he formed a lifelong creative partnership. Neher designed many of the sets for Brecht's dramas and helped to forge the distinctive visual iconography of their epic theatre.

In July 1919, Brecht and Paula Banholzer (who had begun a relationship in 1917) had a son, Frank.  

In 1923, Brecht wrote a scenario for what was to become a short slapstick film, Mysteries of a Barbershop, directed by Erich Engel and starring Karl Valentin. Despite a lack of success at the time, its experimental inventiveness and the subsequent success of many of its contributors have meant that it is now considered one of the most important films in German film history. In May of that year, Brecht's In the Jungle premiered in Munich, also directed by Engel. Opening night proved to be a "scandal"—a phenomenon that would characterize many of his later productions during the Weimar Republic—in which Nazis blew whistles and threw stink bombs at the actors on the stage.

In 1924 Brecht worked with the novelist and playwright Lion Feuchtwanger (whom he had met in 1919) on an adaptation of Christopher Marlowe's Edward II that proved to be a milestone in Brecht's early theatrical and dramaturgical development. Brecht's Edward II constituted his first attempt at collaborative writing and was the first of many classic texts he was to adapt. As his first solo directorial début, he later credited it as the germ of his conception of "epic theatre". That September, a job as assistant dramaturg at Max Reinhardt's Deutsches Theater—at the time one of the leading three or four theatres in the world—brought him to Berlin.

In his role as dramaturg, Brecht had much to stimulate him but little work of his own. Reinhardt staged Shaw's Saint Joan, Goldoni's Servant of Two Masters (with the improvisational approach of the commedia dell'arte in which the actors chatted with the prompter about their roles), and Pirandello's Six Characters in Search of an Author in his group of Berlin theatres. A new version of Brecht's third play, now entitled Jungle: Decline of a Family, opened at the Deutsches Theater in October 1924, but was not a success.

In 1925 in Mannheim the artistic exhibition Neue Sachlichkeit ("New Objectivity") had given its name to the new post-Expressionist movement in the German arts. With little to do at the Deutsches Theater, Brecht began to develop his Man Equals Man project, which was to become the first product of "the 'Brecht collective'—that shifting group of friends and collaborators on whom he henceforward depended." This collaborative approach to artistic production, together with aspects of Brecht's writing and style of theatrical production, mark Brecht's work from this period as part of the Neue Sachlichkeit movement. 

1927 also saw the first collaboration between Brecht and the young composer Kurt Weill. Together they began to develop Brecht's Mahagonny project, along thematic lines of the biblical Cities of the Plain but rendered in terms of the Neue Sachlichkeit's Amerikanismus, which had informed Brecht's previous work. They produced The Little Mahagonny for a music festival in July, as what Weill called a "stylistic exercise" in preparation for the large-scale piece. From that point on Caspar Neher became an integral part of the collaborative effort, with words, music and visuals conceived in relation to one another from the start. 

In 1930 Brecht married Weigel; their daughter Barbara Brecht was born soon after the wedding. She also became an actress and would later hold the copyrights to all of Brecht's work.

Brecht formed a writing collective which became prolific and very influential. Elisabeth Hauptmann, Margarete Steffin, Emil Burri, Ruth Berlau and others worked with Brecht and produced the multiple teaching plays, which attempted to create a new dramaturgy for participants rather than passive audiences. These addressed themselves to the massive worker arts organisation that existed in Germany and Austria in the 1920s. So did Brecht's first great play, Saint Joan of the Stockyards, which attempts to portray the drama in financial transactions.

This collective adapted John Gay's The Beggar's Opera, with Brecht's lyrics set to music by Kurt Weill. Retitled Die Dreigroschenoper (The Threepenny Opera) it was the biggest hit in Berlin of the 1920s and a renewing influence on the musical worldwide. 

The success of The Threepenny Opera was followed by the quickly thrown together Happy End. It was a personal and a commercial failure. At the time the book was purported to be by the mysterious Dorothy Lane (now known to be Elisabeth Hauptmann, Brecht's secretary and close collaborator). Brecht only claimed authorship of the song texts. Brecht would later use elements of Happy End as the germ for his Saint Joan of the Stockyards, a play that would never see the stage in Brecht's lifetime.

The masterpiece of the Brecht/Weill collaborations, Aufstieg und Fall der Stadt Mahagonny (Rise and Fall of the City of Mahagonny), caused an uproar when it premiered in 1930 in Leipzig, with Nazis in the audience protesting. 

Brecht spent the last years of the Weimar-era (1930–1933) in Berlin working with his "collective" on the Lehrstücke. These were a group of plays driven by morals, music and Brecht's budding epic theatre. The Lehrstücke often aimed at educating workers on Socialist issues.  Die Massnahme (The Measures Taken) was scored by Hanns Eisler. In addition, Brecht worked on a script for a semi-documentary feature film about the human impact of mass unemployment, Kuhle Wampe (1932), which was directed by Slatan Dudow. This striking film is notable for its subversive humour, outstanding cinematography by Günther Krampf, and Hanns Eisler's dynamic musical contribution. It still provides a vivid insight into Berlin during the last years of the Weimar Republic.

Fearing persecution, Brecht left Nazi Germany in February 1933, just after Hitler took power. After brief spells in Prague, Zurich and Paris he and Weigel accepted an invitation from journalist and author Karin Michaëlis to move to Denmark. The family first stayed with Karin Michaëlis at her house on the small island of Thurø close to the island of Funen. They later bought their own house in Svendborg on Funen. This house in Svendborg became the residence of the Brecht family for the next six years, where they often received guests including Walter Benjamin, Hanns Eisler and Ruth Berlau. During this period Brecht also travelled frequently to Copenhagen, Paris, Moscow, New York and London for various projects and collaborations.

When war seemed imminent in April 1939, he moved to Stockholm, Sweden, where he remained for a year. After Hitler invaded Norway and Denmark, Brecht left Sweden for Helsinki, Finland, where he lived and waited for his visa for the United States until 3 May 1941. During this time he wrote the play Herr Puntila und sein Knecht Matti (Mr Puntila and his Man Matti) with Hella Wuolijoki, with whom he lived in Marlebäck.

During the war years, Brecht became a prominent writer of the Exilliteratur. He expressed his opposition to the National Socialist and Fascist movements in his most famous plays: Life of Galileo, Mother Courage and Her Children, The Good Person of Szechwan, The Resistible Rise of Arturo Ui, The Caucasian Chalk Circle, Fear and Misery of the Third Reich, and many others.

Brecht co-wrote the screenplay for the Fritz Lang-directed film Hangmen Also Die! which was loosely based on the 1942 assassination of Reinhard Heydrich, the Nazi Reich Protector of the German-occupied Protectorate of Bohemia and Moravia, number-two-man in the SS, and a chief architect of the Holocaust, who was known as "The Hangman of Prague." Hanns Eisler was nominated for an Academy Award for his musical score. The collaboration of three prominent refugees from Nazi Germany – Lang, Brecht and Eisler – is an example of the influence this generation of German exiles had on American culture.

Hangmen Also Die! was Brecht's only script for a Hollywood film. The money he earned from writing the film enabled him to write The Visions of Simone Machard, Schweik in the Second World War and an adaptation of Webster's The Duchess of Malfi.

In 1942 Brecht's reluctance to help Carola Neher, who died in a gulag death camp in the USSR after being arrested during the 1936 purges, caused much controversy among Russian emigrants in the West.

In the years of the Cold War and "Red Scare", Brecht was blacklisted by movie studio bosses and interrogated by the House Un-American Activities Committee. Along with about 41 other Hollywood writers, directors, actors and producers, he was subpoenaed to appear before the HUAC in September 1947. Although he was one of 19 witnesses who declared that they would refuse to appear, Brecht eventually decided to testify. He later explained that he had followed the advice of attorneys and had not wanted to delay a planned trip to Europe. On 30 October 1947 Brecht testified that he had never been a member of the Communist Party. He made wry jokes throughout the proceedings, punctuating his inability to speak English well with continuous references to the translators present, who transformed his German statements into English ones unintelligible to himself. HUAC vice-chairman Karl Mundt thanked Brecht for his co-operation. The remaining witnesses, the so-called Hollywood Ten, refused to testify and were cited for contempt. Brecht's decision to appear before the committee led to criticism, including accusations of betrayal. The day after his testimony, on 31 October, Brecht returned to Europe.

In Chur in Switzerland, Brecht staged an adaptation of Sophocles' Antigone, based on a translation by Hölderlin. It was published under the title Antigonemodell 1948, accompanied by an essay on the importance of creating a "non-Aristotelian" form of theatre. An offer of his own theatre (completed in 1954) and theatre company (the Berliner Ensemble) encouraged Brecht to return to Berlin in 1949. He retained his Austrian nationality (granted in 1950) and overseas bank accounts from which he received valuable hard currency remittances.

Though he was never a member of the Communist Party, Brecht had been schooled in Marxism by the dissident communist Karl Korsch. Korsch's version of the Marxist dialectic influenced Brecht greatly, both his aesthetic theory and theatrical practice. Brecht received the Stalin Peace Prize in 1954.

Brecht wrote very few plays in his final years in East Berlin, none of them as famous as his previous works. He dedicated himself to directing plays and developing the talents of the next generation of young directors and dramaturgs, such as Manfred Wekwerth, Benno Besson and Carl Weber. At this time he wrote some of his most famous poems, including the Buckow Elegies.

Brecht died on 14 August 1956 of a heart attack. He is buried in the Dorotheenstädtischer cemetery on Chausseestraße in the Mitte neighbourhood of Berlin, overlooked by the residence he shared with Helene Weigel.