Kate Marie Nash was born on 6 July 1987 in Brent, North West London, and grew up in Harrow. She developed an interest in music as a child and learned how to play the piano at Sandbach School. She was taught guitar by teacher Saskia van Berkel and studied Theatre at the BRIT School for Performing Arts and Technology in South London.
She auditioned at the Bristol Old Vic Theatre School but was rejected. Soon after, she fell down a flight of stairs, breaking her foot. During her recovery she was restricted to her home, so her mother bought her an electric guitar. Nash used this time to focus on her songwriting.
Nash started her career in 2005. After several gigs, she uploaded her music to MySpace. Her debut was a single, "Caroline's a Victim" / "Birds," produced and recorded in Iceland by Valgeir Sigurðsson and released through Moshi Moshi Records in February 2007. The release was limited to 1,000 copies, and was available on only 7" vinyl.
Due to demand another 1,000 copies were made and sold out. CD-promo copies were produced for distribution to the press and radio stations. It ended up being featured on the CD Moshi Moshi Singles Compilation. A video for the song was released, and appeared on MTV2. The B-side, "Birds," later featured on her debut album, Made of Bricks. Both tracks have also been released as MP3 downloads.
In April 2007, Nash was signed to the Polydor offshoot Fiction Records. Her second single and first through Fiction Records, "Foundations," which she co-wrote with producer Paul Epworth, was released in June 2007 and reached number two on the UK Singles Chart. Following "Foundations," Fiction announced plans to release Nash's debut album, Made of Bricks, in August 2007. The album was commercially successful and reached number 1 in the UK album charts.
Throughout late 2007 and early 2008, she released three more singles from the album. "Mouthwash" and "Pumpkin Soup" both made the Top 40 in the UK Singles Chart, and although fifth single "Merry Happy" didn't chart well in the United Kingdom, the song received limited success in other countries including the US and Canada. In 2010 Made of Bricks was certified Gold in Germany.
In January 2010, Nash revealed that the second album, My Best Friend is You, was complete. The next month, "I Just Love You More," was available to download free from her official website. The first single from the album was called "Do-Wah-Doo," was released the next April, and the album shortly thereafter. The sound was completely different from her debut album. Nash said her maturity caused the change in musical style.
The album has been described as having a wide variety of sounds from wall of sound, Motown to No Wave and Riot Grrrl. By May, the album was number 6 in Germany, number 16 in Europe, and number 62 in the U.S.
As a side project in late 2009, Nash joined a punk band called The Receders where she plays bass. She says in the future, she will focus on her solo material. In March 2010 Nash, a founding director of the Featured Artists Coalition, a musicians' lobbying group, launched the Rock and Roll After-School Music Club an attempt to get secondary school girls involved in songwriting.
Nash is signed to Island Def Jam Ireland Recordings.