Tunstall studied at the High School of Dundee; Madras College in St Andrews; Kent School, Connecticut; and at Royal Holloway. Throughout her twenties she mostly played in independent bands including Elia Drew and Tomoko, and focused on songwriting. She has also written and performed music for children's television shows, but remains secretive as to which shows in particular, preferring her fans to play the guessing game.

Her breakthrough performance was a solo rendition of "Black Horse and the Cherry Tree" on Later with Jools Holland, for which she had twenty-four hours to prepare after scheduled performer Nas cancelled due to his father's ill health. Her performance caught the eye of many viewers, upstaging more established acts such as The Cure, Embrace, and The Futureheads, as she then went on to top the post-show poll on the website for that episode. Her debut album, Eye to the Telescope, was rereleased shortly afterwards, and shot up the U.K. charts, eventually peaking at three (on its first release it had entered at seventy-three); it was nominated for the 2005 Mercury Music Prize. It was released in the U.S. on 7 February 2006.

Tunstall has toured extensively since and plans to record another album sometime in 2006. Since her debut appearance on Later with Jools Holland, she has returned to perform "Suddenly I See", "Under the Weather", "Tangled up in Blue" (she performed the same song, as well as "Simple Twist of Fate" and "This Wheel's on Fire" on a BBC 4 Bob Dylan tribute) and an Ella Fitzgerald song ("Ain't Misbehavin'" by Fats Waller) with Jools Holland on piano. She ended 2005 on New Year's Eve by performing at Edinburgh's Concert in the Gardens alongside Texas, and plans to move back to Edinburgh with her boyfriend, drummer Luke Bullen (The Mescaleros, John Squire).

She uses an AKAI E2 headrush loop pedal on stage, which she affectionately calls "Wee Bastard".

Tunstall sparked some controversy in 2005 when she publicly bashed singer/songwriter Dido, stating that the artist "can't ****ing sing" after several fans compared the two musically. Tunstall later apologised, stating that she did not want to be involved in a public feud.

Due to some of her songs containing ambiguous lyrics, some fans (especially lesbians) were interested to know whether she is also gay, but she has stated that she is not.

On 11 January 2006 she was nominated for three Brit awards: Best British Live Act, British Breakthrough Act, and British Female Solo Artist. At the ceremony on 15 February 2006, Tunstall performed "Suddenly I See" and won the award for Best British Female Solo Artist, remarking that she wished to share it with fellow nominee Kate Bush.

She also appears on the Sophie Solomon song "Lazarus", on the album Poison Sweet Madeira, and provided guest vocals for three tracks, "Ladino Song", "Refugee", and "Yesterday's Mistake", on the Oi Va Voi album Laughter Through Tears (2003). Tunstall also performed "Get Ur Freak On" by Missy Elliott and "High and Dry" by Radiohead at Live Lounge. Tunstall's seventh single, "Another Place to Fall", featured a cover of Radiohead's "Fake Plastic Trees".

Tunstall released a new acoustic album in May 2006, KT Tunstall's Acoustic Extravaganza, which is only available as a CD from her website, although downloadable versions are available from online music shops.

--Wikipedia