Eugene O'Neill was a landmark figure in American theater, as he introduced the realism of European writers like Strindberg, Ibsen, and Chekhov to America. His plays Mourning Becomes Electra, Long Day's Journey Into Night, and The Iceman Cometh all have become standard parts of repertoire for many American theater companies. O'Neill won the Nobel Prize for Literature in 1936.

David Mamet came out of the Chicago theater scene in the late 1970s with a distinctive, fully-formed style with short, snappy dialogue referred to as "Mamet-speak," demonstrated in early work like 1976's American Buffalo. He was immediately considered one of the leading playwrights in America, with his Glengarry Glen Ross winning a Pulitzer Prize for Drama in 1984, and Speed-the-Plow winning the same award in 1988.

Lillian Hellman had an instant Broadway success in 1934 with her first play, The Children's Hour, which also caused controversy over its themes of lesbianism, false accusations, and suicide. The pattern would continue throughout her career, as 1939's The Little Foxes and 1941's Watch on the Rhine both dealt with anti-semitism in America. Both plays were so successful that they were turned into movies with Hellman screenplays.

Brendan Behan joined the IRA as a teenager in the 1940s, and because of crimes he committed against the British government, was imprisoned while still young. Upon being pardoned in 1947, Behan left the IRA behind and began a full-time literary career. An icon of Irish literature, Behan's first two plays, 1954's The Quare Fellow and 1958's An Giall (The Hostage), both depicted life in an Irish prison like the ones in which Behan was held.

A Raisin in the Sun was considered a risky proposition when it was first produced on Broadway in 1959, dealing as it did with the story of an African-American family. The play proved to be a success anyway, helping launch not only Hansberry's career, but also that of actor Sydney Poitier. The play was the first on Broadway with a cast that had an African-American majority.

Beginning with his play 1982 play Jitney, August Wilson undertook a project to write one play representing each decade of the twentieth century that took on the African-American experience. All but one, 1984's Ma Rainey Black Bottom took place in Pittsburgh, often featuring members of the same family. Two of the plays won Wilson the Pulitzer Prize for Drama, 1987's Fences and 1990's The Piano Lesson.

Many critics and scholars group Blood Wedding, The House of Bernarda Alba, and Yerma as a trilogy, as they all deal with rural Spain and were composed from 1932 to 1936. Their author, Federico Garcia Lorca, had actually intended to write a third play to make a trilogy, and did not himself see The House of Bernarda Alba in the trilogy. Lorca was killed by Nationalist forces in the Spanish Civil War in 1936, for his activity on behalf of the Republican forces, which often was apparent in his writings.

John Guare emerged in the 1960s with a wave of other playwrights, but distinguished himself through wry humor and interesting narrative form, both of which he applied to conventionally dramatic stories. The House of Blue Leaves (1966) is a black comedy about nuns, the Vietnam War, and mental institutions that features many characters coming and going. Six Degrees of Separation (1990) tells the story of a con man's deception of socialites from the socialites' perspective at a dinner party.

A Streetcar Named Desire won the 1948 Pulitzer Prize in Drama for its playwright, Tennessee Williams. Largely considered one of the premier dramas of the twentieth century, the play's depiction of mental health problems, sexual desire, and violence was considered groundbreaking in its own time. The play would be made into an award-winning movie in 1951 and firmly established Tennessee Williams as one of the largest figures of the theater world.

Arthur Miller won the Pulitzer Prize in Drama in 1949, David Mamet won the Pulitzer Prize in Drama in 1984, Eugene O'Neil won the Pulitzer Prize in Drama in 1922, 1928, and 1957, and Sarah Ruhl won the Pulitzer Prize in Drama in 2010.