American bluegrass fiddler and singer who—alone and in collaboration with her band, Union Station—performed folk (folk music), gospel (gospel music), country (country music), pop, and rock (rock and roll) songs in the unamplified bluegrass style and played a major role in the early 21st-century revival of interest in bluegrass music.

Krauss began studying classical violin at age five but proved to be a bluegrass prodigy. A flamboyant fiddler, she won several contests, led a band when she was 10, won the Illinois State Fiddling Championship two years later, and signed a recording contract at age 14. In 1990 she won a Grammy Award for her third album, I've Got That Old Feeling. Krauss's first incarnation of Union Station included her bass-playing older brother, Viktor, who later joined Lyle Lovett's backing band. As Union Station evolved and changed, Krauss's soprano singing became a primary element in its success. By 1995 the ensemble was a leading bluegrass act with the breakthrough album Now That I've Found You and the hit single "When You Say Nothing at All." Each of Krauss's successive efforts became best sellers as well, and her performances on the soundtracks for the films O Brother, Where Art Thou? (2000) and Cold Mountain (2003) helped to introduce bluegrass to a new audience.

In 2004 the million-selling Alison Krauss + Union Station Live was awarded the Grammy for best bluegrass album; "Cluck Old Hen," which showcased Krauss's fiddle, won best country instrumental; and her duet with pop artist James Taylor (Taylor, James), "How's the World Treating You," was named best country collaboration with vocals. With those wins, Krauss passed soul (soul music) legend Aretha Franklin (Franklin, Aretha) to become the female artist with the most Grammys. She earned an additional three Grammy Awards for Lonely Runs Both Ways (2004) and another for the duet "Gone Gone Gone" with Led Zeppelin front man Robert Plant. That single appeared on the album Raising Sand (2007), a project that brought together Krauss, Plant, and producer T-Bone Burnett. Burnett, who had worked with Krauss on the O Brother, Where Art Thou? and Cold Mountain soundtracks, crafted a sound that was equal parts Appalachian roots music, power pop, and guitar-driven rock, tied together by the distinctive vocals of Krauss and Plant. The album was a massive crossover success, hitting number two on the Billboard pop and country charts, and Krauss and Plant embarked on a world tour to support it.