Siobhan Donaghy is of Irish and Moroccan descent and has been performing since she was 12 years old. She was discovered by former All Saints manager Ron Tom, who went on to manage Sugababes The group was created when Keisha Buchanan and Mutya Buena, friends since they were only eight years of age, met Donaghy at a 1998 party when they were thirteen, and were introduced by manager, Ron Tom. Buena and Donaghy had been working separately with Tom, and while they were recording it was suggested that they would try it with a third member. Buchanan had been invited to come along to watch by Buena and was asked if she could sing; the name 'Sugababes was made up by their manager Ron Tom. At fourteen, they were offered a record contract by London Records and started calling themselves the Sugababes Their debut single "Overload" was very successful in the United Kingdom and was nominated for a BRIT Award for "Best Single", climbing #3 in Germany and #2 in New Zealand. Their debut album produced three more hits in the United Kingdom: "New Year", "Run For Cover" and "Soul Sound".

The Sugababeshad been following a heavy touring schedule for over a year with Donaghy gradually becoming unhappy with her position in the band. Feeling that the other girls were trying to force her out, Donaghy decided to leave of her own accord and did so during a Japanese promotional tour. Her management initially stated that she left because she wanted to pursue a fashion career. According to Siobhan herself, she left the band because she never got along with Keisha, whom she described as a bully. She became deeply depressed and could no longer be a part of the band.

Donaghy started writing music along with the help of former producer Cameron McVey (who has worked with Sugababes All Saints and Neneh Cherry) to help overcome her depression, and began performing under the alias of "Shanghai Nobody". In March 2003, Donaghy released "Nothing But Song" under this title as she did not want to be known as "The girl who left the Sugababes. "Nothing But Song" was released as a 7" vinyl single only and was relatively unknown. Upon the release of her first commercial single, "Overrated", Donaghy reverted back to her given name.

On June 23, 2003 she released her first commercial solo single followed. "Overrated", co-written with Cameron McVey, peaked at #19 in the United Kingdom. The title of the lead single, "Overrated", is a play on words on Sugababes debut single, "Overload". Following up "Overrated", the single "Twist Of Fate" was released on September 15, 2003 and charted at #52. Two weeks later saw the release of her debut album Revolution In Me.

The album Ghosts was released on June 25, 2007, but with no radio support it peaked at #92 and then fell out of the charts. The album was recorded in a small studio near Barneville-Carteret, France. Producer James Sanger has worked with artists such as U2 Keane, and Dido Due to commitments for her role in West End musical RENT, promotion for the album has been put on hold. Siobhan is expected to recommence promotion of the album in 2008 and also begin work on her third album.