In the first few seasons, Willow was a shy, naïve loner with a light, risqué sense of humor. A member of the Math, Science and Computer clubs, she was the person to go to for tutoring help. She was ridiculed by her more popular classmates, including cheerleaders Cordelia Chase and Harmony Kendall. A fledgling hacker, she was one of two students at Sunnydale High to be selected to be wooed by an unnamed, but very prestigious software company, and was chosen to teach computer science after Jenny Calendar was murdered. She had a hopeless crush on her childhood friend Xander Harris, who ignored her to pursue his equally hopeless crush on Buffy Summers and later, a relationship with Cordelia Chase. Before Xander developed feelings for the latter, he and Willow had been charter members of the "We Hate Cordelia" Club.
Willow soon became Buffy's best friend. When they discovered Calendar's secret project, Willow told Buffy that she had gone through her former favorite teacher's belongings, and dabbled in magic. After performing the Ritual of Restoration, she continued to learn magic even though she did not learn of her success in restoring Angel's soul until "Faith, Hope & Trick". She developed a romantic relationship with Daniel 'Oz' Osborne, a guitarist in the local band Dingoes Ate My Baby, which survived Oz's revelation as a werewolf and a kiss with Xander while being held hostage. She also met her demonic alter ego in season three's "Doppelgängland", where her vampire Doppelgänger counterpart groped the "real" Willow as well as Xander.
At UC Sunnydale, Willow and Buffy moved across town to Room 214 in Stevenson Hall. After Oz's dramatic departure, Willow joined the campus Wicca group, a disappointing experience but for the presence of Tara Maclay. After discovering each other's magic, they became friends and later, lovers and soulmates, sharing one of the few lesbian relationships portrayed in American television. Although she manifested a crush for Xander early on in the series and established a long-running and sexually active relationship with Oz before coming out as a lesbian, it is not an uncommon experience for lesbians to go through.
Willow's magical skills first peaked in "Bargaining", the season six opener. She led Tara, Xander and Anya in raising Buffy from the dead. Afterwards, she became addicted to using magic. Her disregard for the consequences of her actions eventually drove Tara away and Buffy's sister Dawn to the hospital. With Tara's departure, Willow was forced to face her problem and stopped using magic. When Tara was murdered by serial killer Warren Mears, however, a grief-stricken Willow unleashed the dark energies once more, and her vengeance reached a climax when Willow magically skinned Mears alive. Willow absorbed volumes of magic as she pursued the other members of the Trio, Mears' accomplices, turning against her friends in the process. Her attempt to raise an apocalypse was ended by Xander's words of friendship.
Willow retreated to England with Buffy's Watcher Rupert Giles, but was forced to deal with her magical nature and her place in the universe. In an important crossover, she battled Jasmine, the then villain on Angel and restored Angel's soul. She returned from Los Angeles with Faith, a reformed Slayer. Willow slowly regained control of her powers and entered a new relationship with potential Slayer Kennedy. In the series finale, "Chosen", Willow was able to use her powers to change the rules for the Slayer line.
Buffy: "In each generation one slayer is born. One girl in the whole world is chosen. One girl with the strength and power to kill vampires. Why is this? Because three men decided so thousands of years ago. This woman (pointing to Willow) is more powerful than all of them together".
Following "Chosen", the fifth season of Angel continued the "Buffyverse," mentioning Willow spending some time with Kennedy in Rio de Janeiro, Brazil and traveling to an unreachable plane of existence.
