Keisha Kerreece Fayeanne Buchanan was born on 30 September 1984 in London, United Kingdom. She attended Kingsbury High School, and it was during this period in London that she became a founding member of the girl group Sugababes, forming the act alongside Mutya Buena and Siobhán Donaghy. Working in the English language and rooted in pop music, Buchanan has worked as a singer, songwriter, and composer.

As a founding member of the Sugababes, Buchanan was part of a group that achieved six number-one singles and two number-one studio albums. Her work with the group placed her among the active participants in British pop music. In September 2009, however, Buchanan was sacked from the Sugababes and replaced by Jade Ewen, bringing her initial period with the group to a close.

Buchanan's connection to the group she helped found did not end permanently with her departure. In 2012, she returned to the Sugababes as part of a reconvened original line-up, reuniting with Mutya Buena and Siobhán Donaghy — the same founding members with whom she had first formed the act in London. Her return to the original line-up in 2012 represents the most recent development recorded in her association with the group she co-founded.