Jarosz was born in Austin, Texas, on May 23, 1991, where her parents were teachers. She first picked up the mandolin when she was ten years old, and by the time she was 12, she was jamming with the likes of David Grisman and Ricky Skaggs on-stage. As her gifts as a songwriter became better known, she developed a buzz as a next-generation version of Gillian Welch, and Jarosz signed a deal with Sugar Hill Records when she was just 16. A debut album, Song up in Her Head, appeared from the label in 2009 and quickly garnered tremendous critical acclaim. That same year, Jarosz began work on a major in contemporary voice improvisation at the New England Conservatory of Music, hardly the province of a typical bluegrass musician. A second long-player, Follow Me Down, appeared from Sugar Hill in the spring of 2011. Jarosz recorded her third album, Build Me Up from Bones, during her final semester in school. It contained nine originals and a pair of covers: Bob Dylan's "A Simple Twist of Fate" and Joanna Newsom's "Book of Right-On." The set was issued by Sugar Hill in September 2013.
After extensive international touring, Jarosz was selected by Garrison Keillor to act as an occasional guest host for his successful radio program A Prairie Home Companion. Jarosz relocated to New York City, a transition readily reflected in her work. She reentered the studio in 2015 with co-producer Gary Paczosa. Playing guitar, octave mandolin, and banjo, she was accompanied by Jedd Hughes, Luke Reynolds, and Mark Schatz. Sara Watkins and Aoife O'Donovan (her bandmates in the trio I'm with Her) appeared on the track "Still Life." The completed album, Undercurrent, was released in June 2016 by Sugar Hill. Later that summer, Jarosz and O'Donovan were named to the newly formed house band for A Prairie Home Companion under host Chris Thile, who took over for Keillor in October; they remained part of the show when it was rebranded as Live from Here in late 2017.
The following year, Jarosz joined Watkins and O'Donovan in the studio to record I'm with Her's debut album, See You Around, for Rounder Records. A critical success, the release won a Grammy Award for Folk Album of the Year. Returning to solo work, Jarosz earned similar honors for her fifth album, 2020's World on the Ground, which won the Grammy for Best Americana Album. Inspired by childhood visits to the Gulf Coast town of Port Aransas, Texas, Jarosz released the poignant, Grammy-nominated Blue Heron Suite in May 2021. ~ Steve Leggett & Mark Deming, Rovi