Alison was born in Gardendale, New York to Carter and Katherine Blaire. Her mutant powers first manifested when she was in high school. An aspiring singer, she volunteered to perform at her school dance when her light-generating abilities first appeared. Everyone at the dance assumed it was a technologically-generated special effect, an assumption commonly made before she reveals herself to be a mutant later in her life.
Using the stage name "Dazzler", Alison sets out to make a name for herself in the music industry, using her light powers and dancing ability to enhance her performances. It is at one of her shows that Alison first meets the X-Men who are attacked by the forces of the Hellfire Club. Angry at the interruption of her show, Alison lashes out in anger at the Hellfire intruders, unintentionally making one of them catatonic. Alison subsequently aids the X-Men in finding Kitty Pryde. She had always assumed that life as a disco queen would be exciting but finds the fight with the X-Men's enemies going a bit too far. Thus she turns down their offer to join the team.
Dazzler hides her status as a mutant from all but those closest to her. After acquainting herself with the various Marvel Comics superheroes, Alison finds herself continually using her abilities to fight both ordinary criminals and rogue superhumans — often at the expense of her career ambitions. On one occasion, she meets Spider-Man, and teams with him against the Lightmaster. She later battles the Enchantress, is overwhelmed by Doctor Doom, the Absorbing Man and then fights off Nightmare. She briefly allies with the Blue Shield, and aids the X-Men and Spider-Woman against the misguided Caliban. On another occasion, she battles the Hulk and establishes a long standing feud with the then-mentally unstable Rogue. She also had a romantic affair with Warren Worthington III. In the course of her inadvertent adventures, she even encounters the planet-devouring Galactus, who initially thinks she is of little notice and generally ignores her. Nevertheless, he temporarily endows her with cosmic energy so she can retrieve his herald Terrax for him. In addition to being offered membership into the X-Men, Alison is also asked to audition for a place in the Avengers. She declines while facing Fabian Stankowicz (who is ultimately easily defeated by the Wasp), saying that the superhero "trip wasn't for her."
After moving to Los Angeles in a vain attempt to help her half-sister Lois London, who has the mutant ability to kill anyone she touches, but has little to no control over her abilities, Alison attempts careers in fitness training, dancing, modeling, and acting. Influenced both by her lover, Roman Nekoboh, and her desire to abate the growing anti-mutant sentiment, Alison publicly declares her mutant identity. The revelation backfires, destroying her reputation and career and inflaming anti-mutant sentiment, which sends Alison into a depressive state. Forced again into hiding, she spends some time as a keyboard player in rock singer and fellow mutant Lila Cheney's band. While on tour, the band's plane crashes, which leads to Dazzler, Lila, and a bandmate being successfully rescued by Cannonball and his brother, Joshua. Lila has been knocked out so Dazzler uses the music Joshua plays at the scene to blast a hole through the wreckage. Alison is later possessed by the psychic mutant Malice. She is saved and taken in by the X-Men, becoming a member of the team.
During her tenure with the X-Men, Dazzler receives training, attains greater control over her powers, and develops a romance with the extra-dimensional Longshot. She is also forced to work alongside the now-reformed Rogue. This causes considerable tension between them at first, due to Alison's difficulty in getting over Rogue's attempts to kill her in the past, as well as Rogue's own strong feelings for Longshot. Over time she eventually believes Rogue is genuinely remorseful and forgives her. Dazzler struggles with her career ambitions and personal insecurities, and eventually she and her team-mates in the X-Men enter the mystical Siege Perilous, which leaves her in an amnesiac state. Discovered washed up on a beach by her former bodyguard Strong Guy, she is nursed back to health by him and Lila Cheney, though their efforts prove unsuccessful in helping restore her memory. It is eventually restored when she is found by Longshot. Devastated by the loss of her career, Alison ventures to Longshot's native "Mojoworld", and remains there to help fight in the ongoing rebellion against the tyrant Mojo along with Lila Cheney.
Dazzler eventually returns to Earth without Longshot after an unfortunate series of events, including miscarriage and war. She helps Jean Grey in the fight against a repowered Magneto, who is backed by an army of Genoshans. She and Jean lead a small band of mutants to back up the original X-Men, who are in Genosha already. Dazzler faces down Magneto who turns her powers against her and incinerates her. As he arrogantly boasts about his triumph, Dazzler reveals herself to be alive and well. She and Jean had concocted a plan for Alison to generate a hard-light hologram of herself to distract Magneto who was then killed by Wolverine. After the conclusion of this incident, the X-Men offer Alison support for her personal problems, but she declines.
Characters in the Marvel Universe who are counted among her musical fans are Juggernaut, teammate Colossus, the Hulk, Northstar, Julia Carpenter, The Rhino, Molly Hayes, Shadowcat and Pixie.
Dazzler later re-establishes her musical career, marketing her trademark disco image as part of the Techno/Trance genre. Alison moved her career abroad to England and joined with X-Men allies such as the Juggernaut and Captain Britain. She was reunited with Longshot in the X-Men: Die by the Sword miniseries, although Longshot was suffering from amnesia and did not remember her. However, during the course of the miniseries he regained his feelings for her and some of his memories. Longshot left the Exiles to reestablish his relationship with Dazzler but the couple split ways due in part to Dazzler's frustration with other women's attraction to Longshot (which is a part of his power set), but mainly because of the realization that Longshot was no longer the man she loved because of his amnesia.
As of Uncanny X-Men #500, Alison rejoins the X-Men in San Francisco after leaving Longshot, due to the fact that their relationship was just not the same after his loss of memory. Pixie is seen leaving a club with a friend where Alison has recently performed. Dazzler requests Pixie to join her on stage in future shows due to Pixie's mutant abilities, but Pixie declines the offer. Dazzler has established a career as a musician, finally landing a big break. Dazzler has also been shown to take part in the X-Men: Secret Invasion mini-series, which is part of Marvel Comics' 2008 crossover, Secret Invasion. Returning home with Northstar and Pixie, after taking her out to get drunk, despite her being underage, Dazzler and the team are unprepared for a brutal attack on the mansion by the Sisterhood. In retaliation, Dazzler later accompanies Emma Frost, Storm, and Karma for the revenge-attack on the Sisterhood in San Francisco where she engages a mind controlled Psylocke, who was back in her original body, in battle. While Psylocke gains the upper hand, Dazzler points out that Storm blew out all the windows when they entered. This was so she could absorb all the sound from the city outside, which she turned into a beam of light that burns the right side of Psylocke's face off. After the Sisterhood retreats Dazzler is happily reunited with Psylocke, who regains control of her Japanese body.