Solanas was born in Ventnor City, New Jersey to Louis Solanas and Dorothy Biondi. She claimed that she regularly suffered sexual abuse at the hands of her father. Her parents divorced when she was 11, and her mother remarried shortly afterwards. Solanas disliked her stepfather and began rebelling against her mother and became a truant. Because of her rebellious behavior, her mother sent her to be raised by her grandfather in 1949. Solanas claimed that her grandfather was a violent alcoholic who often beat her. When she was 15, her grandfather kicked her out, rendering her homeless. In spite of this, she graduated from high school with her class and earned a degree in psychology from the University of Maryland, College Park.

She did nearly a year of graduate work in psychology at University of Minnesota. In 1953, she gave birth to a son, David. Other details of her life until 1966 are unclear, but it is believed she traveled the country as an itinerant, supporting herself by begging and prostitution.

Solanas arrived in Greenwich Village in 1966, where she wrote a play titled Up Your Ass about a man-hating prostitute and a panhandler. In 1967, she encountered Andy Warhol outside his studio, The Factory, and asked him to produce her play. Intrigued by the title, he accepted the script for review. According to Factory lore, Warhol, whose films were often shut down by the police for obscenity, thought the script was so pornographic that it must be a police trap. He never returned it to Solanas. The script was then lost, not to be found until after Warhol's death, in the bottom of one of his lighting trunk.

Later that year, Solanas began to telephone Warhol, demanding he return the script of Up Your Ass. When Warhol admitted he had lost it, she began demanding money as payment. Warhol ignored these demands but offered her a role in I, a Man. In his book The Warhol Sixties, Warhol wrote that before she shot him, he thought Solanas was an interesting and funny person, but that her constant demands for attention made her difficult to deal with and ultimately drove him away.

Warhol did give Solanas a role in a scene in his film I, a Man (1968—1969). In that film, she and the film's title character (played by Tom Baker) haggle in an apartment building hallway over whether they should go into her apartment. Solanas dominates the improvised conversation, leading Baker through a dialogue about everything from "squishy asses", "men's tits", and lesbian "instinct". Ultimately, she leaves him to fend for himself, explaining "I gotta go beat my meat" as she exits the scene.

During the late 1960s, Solanas wrote and self-published her best-known work, the SCUM Manifesto, a text which reads as a scathing, misandric attack on the male sex. SCUM is generally held to be an acronym of "Society for Cutting Up Men", although it does not appear in the manifesto itself, and is actually a backronym. The opening words of the Manifesto immediately refer to its directives:

Attempted assassination of Andy Warhol

On June 3, 1968, she arrived at The Factory and waited for Warhol in the lobby area. When he arrived with a couple of friends, she produced a handgun and shot at Warhol three times, hitting him once. She then shot art critic Mario Amaya and also tried to shoot Warhol's manager, Fred Hughes, but her gun jammed as the elevator arrived. Hughes suggested she take it and she did, leaving the Factory. Warhol barely survived; he never fully recovered and for the rest of his life wore a corset to prevent his injuries from worsening.

That evening, Solanas turned herself in to the police and was charged with attempted murder and other offenses. Solanas made statements to the arresting officer and at the arraignment hearing that Warhol had "too much control" over her and that Warhol was planning to steal her work. Pleading guilty, she received a three-year sentence in a psychiatric hospital. Warhol refused to testify against her.

The attack had a profound impact on Warhol and his art, and The Factory scene became much more tightly controlled afterward. For the rest of his life, Warhol lived in fear that Solanas would attack him again. "It was the Cardboard Andy, not the Andy I could love and play with," said close friend and collaborator Billy Name. "He was so sensitized you couldn't put your hand on him without him jumping. I couldn't even love him anymore, because it hurt him to touch him." While his friends were actively hostile towards Solanas, Warhol himself preferred not to discuss her.

One of the few public pronouncements in her favor was distributed by Ben Morea, of Up Against the Wall Motherfuckers/Black Mask fame. It was later re-printed as an appendix in the Olympia Press edition of her manifesto.

It is widely believed that Solanas suffered from paranoid schizophrenia at the time of the shooting. A psychiatrist who evaluated her shortly thereafter concluded that she was "a Schizophrenic Reaction, paranoid type with marked depression and potential for acting out." As a result, many of her detractors derided her as a "crazed lesbian".

In 2009, Margo Feiden, a former Broadway producer and playwright, claimed that she had been visited by Solanas on the morning of the shooting. According to interviews with The New York Times and Interview magazine, Feiden received a manuscript from Solanas but refused to stage it. Feiden believes that Solanas "did that shooting as a publicity stunt to be famous, so that I would produce her play." Feiden said that she tried to avert the shooting by calling a relative of Warhol and authorities and that nobody took her calls seriously.

Feminist Robin Morgan (later editor of Ms. magazine) demonstrated for Solanas' release from prison. Ti-Grace Atkinson, the New York chapter president of the National Organization for Women (NOW), described Solanas as "the first outstanding champion of women's rights." Another member, Florynce Kennedy, represented Solanas at her trial, calling her "one of the most important spokeswomen of the feminist movement."

After her release from prison in 1971, she persisted in stalking Warhol and others over the telephone, however, she was arrested again. An interview with her was published in the Village Voice in 1977. She denied that the SCUM Manifesto was ever meant to be taken literally. Solanas drifted into obscurity and was in and out of mental hospitals.

Later life

Ultra Violet, according to her somewhat unreliable report,Violet, Ultra. Famous For 15 Minutes: My Years With Andy Warhol. N.Y.: Avon Books (1st Avon Books Trade Printing Apr. 1990, © 1988) (ISBN 0-380-70843-4), p. v (Disclaimer) (esp. "I have taken artistic license in conveying both reality and essence" & "[s]ome conversations . . . are not intended . . . as verbatim quotes."). interviewed her. Solanas was then known as Onz Loh and apparently had not written anything other than SCUM Manifesto. Solanas stated that the August 1968 version of the Manifesto had many errors, unlike her own printed version of October 1967, and that the book had not sold well. She also reported that, until told by Ultra, she was unaware of Andy Warhol's death.

Death

On April 25, 1988, at the age of 52, Solanas died of pneumonia at the Bristol Hotel in the Tenderloin district of San Francisco. More than 30 years after the loss of Up Your Ass, it was re-discovered. In 2000, the play premiered in San Francisco, only blocks from the hotel where she died.