Born in 1979, Michaelson was raised on New York's Staten Island by her artist mother and classical composer father. There, she began exploring music with piano lessons at the age of four, and developed her performance skills studying at Manhattan's Third Street Music School, the Jewish Community Center of Staten Island's Dorothy Delson Kuhn Music Institute, and Staten Island Technical High School. After high school, she attended Binghampton University, where she earned her theater degree and participated in a cappella and improv groups. Upon graduating, she toured with a national theater troupe and spent her free time writing songs, later compiling them into an online-distributed recording entitled Slow the Rain.
Michaelson blazed her own trail by independently issuing her proper debut, the engaging Girls and Boys, in 2006; following the inclusion of her music in several episodes of Grey's Anatomy, she then released a remastered version of the album on her own Cabin 24 Records in January 2007. Three months later, she won a national songwriting contest sponsored by Mountain Stage, a radio program produced by West Virginia Public Broadcasting and distributed worldwide. "The Way I Am" was then picked up by a major clothing brand, which used it to soundtrack one of their commercials, and Michaelson began making headlines as one of the country's most promising independent artists. A benefit project comprising live recordings, new songs, and rarities, Be OK was released in 2008. Michaelson joined the Hotel Cafe Tour that fall in support of the album, whose proceeds went toward cancer research. She later toured Europe alongside Jason Mraz.
For her "proper" follow-up to Girls and Boys, Michaelson retreated to a Manhattan studio alongside producer Dan Romer. Forty newly composed songs were whittled down to a total of 12, with more emphasis being paid to the songwriter's peppier material. Featuring a string section on several songs, 2009's Everybody proved to be Michaelson's most expansive, confident effort to date, and she followed its release with another cross-country tour. In 2012, she returned with her fifth studio album, Human Again, with production from David Kahne (Paul McCartney, Regina Spektor, the Bangles) and featuring the single "Ghost." It earned critical praise and performed even better on the Billboard 200, reaching number five. Its chart placement was duplicated by the follow-up, Lights Out, which arrived in April 2014 featuring a number of songwriting collaborations and guest appearances, including Mat Kearney, A Great Big World, and then-husband Greg Laswell.
In the spring of 2016, Michaelson teased her seventh album with the hooky breakup single "Hell No," which she co-wrote with country songwriters Barry Dean and Luke Laird. The album, It Doesn't Have to Make Sense, appeared in late August of that year and featured more intensely personal material than her previous LP. She followed up in May 2017 with a companion EP titled Alter Egos, which comprised reinterpretations of songs from the album. It included guest appearances from Tegan and Sara, Lucius, Sara Bareilles, and others. In 2018, she issued the holiday-themed full-length Songs for the Season; it reached number three on the Billboard Holiday Albums chart and number 94 on the Billboard 200.
In May 2019, Michaelson released "Missing You," the first single off her Stranger Things-inspired album, Stranger Songs. The LP followed in June -- the week before the Netflix series' Fourth of July season three premiere -- and peaked at number two on the Billboard Top Independent Albums chart. An Emmy nomination for Outstanding Original Music and Lyrics for "Build It Up" from the Hulu mini-series Little Fires Everywhere followed in 2020. A year later, Michaelson teamed up with ZAYN for the empowering single "To Begin Again." ~ Katherine Fulton & Andrew Leahey, Rovi