[3] Galás's commitment to addressing social issues and her involvement in collective action has made her concentrate on themes such as AIDS, mental illness, despair, loss of dignity, political injustice, historical revisionism, and war crimes.

[4][5] Galás has attracted the attention of the press particularly for her voice – a soprano sfogato – and written accounts that describe her work as original and thought-provoking refer to her as "capable of the most unnerving vocal terror",[2] an "aesthetic revolutionary",[6] "a mourner for the world's victims" and "an envoy of risk, honesty and commitment".

[20][21] Outside academia, Galás's vocal training was supported by private lessons in San Diego with bel canto tutor Frank Kelly, and with voice coaches Vicky Hall in Berlin and Barbara Maier Gustern in New York.

[22] In the early 1970s, Galás and her friend contra-bass player Mark Dresser joined the jazz band Black Music Infinity, which included drummer Stanley Crouch, trumpeter Bobby Bradford, cornetist Butch Morris, flautist James Newton, and saxophonist David Murray.

She later collaborated with members of the San Diego band CETA VI, which included, among others, jazz saxophonist Jim French, with whom Galás went on to record and release her first compositions, as part of the album If Looks Could Kill (1979), together with guitarist and sound engineer Henry Kaiser.

It was a performance of Vinko Globokar's Un Jour Comme un Autre (A Day Like Any Other), an opera based on Amnesty International's documentation about the arrest and torture of a Turkish woman for alleged treason.

[18][23][24] Globokar was the director of the Instruments and Voice department at the music and sound research center IRCAM (Institut de Recherche et Coordination Acoustique/Musique), where Galás had been doing further experimentation on her vocal technique.

[25][8] During her time in Paris, Galás also met the Greek composer and architect Iannis Xenakis, whose composition Akanthos (1977) she sang with IRCAM's Ensemble InterContemporain in 1980, while she was still in Europe.

[26] After her return to the US, Galás performed one more work by Xenakis, his composition N'Shima (1975), in the US premiere of it in New York in 1981, alongside soprano Genevieve Renon-McLaughlin, who sang one of the two vocal parts of this piece.

Shortly after the recording of the trilogy's first volume began, her brother, playwright Philip-Dimitri Galás, became sick with AIDS, which inspired her to join activist groups that raised awareness about this new illness.

[34][18] Taking a break from her own recordings, Galás appeared on the 1989 studio album Moss Side Story by Barry Adamson (formerly of Magazine and Nick Cave and the Bad Seeds).

[34] For her next record, Galás changed stylistic direction by turning to the blues tradition and interpreting a wide range of songs with only a piano and solo voice.

In 1995, Galás contributed vocals to the eponymous album of British synth-pop duo Erasure at the invitation of the lead singer, Andy Bell,[38] and the following year she took part in the album Closed on Account of Rabies, a tribute to Edgar Allan Poe which also included Iggy Pop, Debbie Harry and Marianne Faithfull, who lent their voices to the tales of the legendary author.

[42] One of the unaccompanied vocal pieces from Defixiones: Will and Testament (2003), "Orders from the Dead", was later used on the album Aealo (2010) by Greek black metal band Rotting Christ.

[5] Commentators suggest that Galás's paintings look to the past by presenting stylistic similarities with artworks by Expressionist artists such as Edvard Munch, Paul Klee and Jean Dubuffet.

[60][61] One of the Expressionist artists that Galás mentions as influential to her is the Austrian painter and playwright Oskar Kokoschka, especially with his short play Murderer, the Hope of Women (1909), which has very little text but creates 'explosions' by being immensely expressive.

[62] Galás has also been compared to the artist David Wojnarowicz, whose work is seen as falling within the wider limits of neo-expressionism, for the similarities in which they invite horror through immediate and explicit expression.

[68][69] In 2010, a four-minute video artwork entitled A Fire in My Belly (1992), which was made using a composition by Galás from her album Plague Mass (1991) and a film by the artist David Wojnarowicz, was featured in the exhibition Hide/Seek at Smithsonian's National Portrait Gallery.

[70][71] In 2011, Galás collaborated with Soviet dissident artist Vladislav Shabalin on Aquarium, a sound installation inspired by the environmental disaster in the Gulf of Mexico.

[73][74][75] In July 2020, Galás presented via Fridman Gallery's online space a work inspired by poetry and visuals related to physical and mental scars in soldiers who were injured in the First World War.

[82][83] Most recently, Galás contributed work to James Wan's 2013 horror film, The Conjuring, and her composition "Free Among the Dead" from the album The Divine Punishment (1986) was featured in Zoe Mavroudi's documentary, Ruins: Chronicle of an HIV Witch-Hunt (2013).

Galás was mentioned in Michael Kustow's autobiographical book One in Four (1987), which uses the form of a journal to tell the author's story for the year 1986, when he was working as a Commissioning Editor for the Arts in the British TV station Channel Four.

Galás's name does not appear directly in the book, but several references to her are made in a conversation between the author and the owner of the independent music label Some Bizzare Records Stevo Pearce, such as the use of cutting-edge technology in her live performances, her singing technique, and her Greek heritage.

[89] Art historian Nicholas Chare discusses the concert performance Todesfuge (Death's Fugue) by Diamanda Galás in his study Auschwitz and Afterimages: Abjection, Witnessing and Representation (2011).

[90] Galás has cited multiple artists as influences on her music, including Maria Callas, Annette Peacock, Patty Waters, John Lee Hooker, Johnny Cash, Ray Charles, and Jimi Hendrix.

[9] Galás has also expressed admiration for the comedian Don Rickles, who she has called "my hero", as well as the work of poets such as Henri Michaux and Georg Heym, and an array of other musicians, including Chet Baker, Doris Day, The Supremes, Gladys Knight, Miki Howard, Whitney Houston, Amy Winehouse and Adele.