Kate Ryan was born to Dutch parents in a small village named Tessenderlo in Belgium. She grew up in a musical family, and had talent for music at a very early age. At eight years old she had learned to play the piano and guitar, and could easily learn to play anything she heard on the radio. She had singing and piano lessons from her aunt who teaches at a conservatory, but had other interests too. She studied at an art school, specializing in jewelry design.

Ryan played frequented bars and cafés as a teenager, and one night a manager approached her, wanting her to record a song in a studio. She became a member of a pop group called Melt at the age of 16. The group was active for two years, but they did not release any material commercially. When she met with producer Andy Janssens, she left Melt and the pair began to write music together. Their debut single "Scream For More" was released in 2001, and it became an unexpected chart success.

She gained international prominence with a cover of Mylène Farmer's "Désenchantée", which was a hit on various European pop music charts. She signed with EMI Belgium and released her first album Different in 2002 exclusively in Europe. The album went Gold, selling more than 250,000 copies throughout Europe.

It became popular enough in the States and music consumers who favour dance-pop with an European flavour bought Different even though it was only available as an import title.

In 2004 Ryan released a second album in Europe, and in 2005 it was released in North America on Water Music Records; the album was named Stronger, with two more popular songs—"Another Day" and "The Rain" which were rumored to have been inspired by the twilight series. While the album did well on the dance charts, it failed to chart on the pop charts because of poor promotion.

In 2006 she participated in Eurosong '06, the national final to select the entrant for Belgium in the Eurovision Song Contest 2006. She was selected as the entrant after placing first in the Eurosong final on March 9, 2006. Ryan represented Belgium at the Eurovision semifinal held on May 18, 2006 in Athens singing "Je t'adore". She did not qualify for the final, however, finishing two places outside the advancing Top 10 (12th) with 69 points.

The following single was "Alive", taken from the album of the same name, which also features French versions of several tracks including "Je T'Adore", "Alive", and the third single "All For You".

In 2007, she had some success with the double sided single "Voyage Voyage"/"We All Belong". The track "Voyage, Voyage" is a cover of the 1987 European smash hit by Desireless, and "We All Belong" was selected as the official anthem for the Eurogames 2007.

In 2008, she released two singles: L.I.L.Y. (Like I Love You) and then Ella, Elle L'a. Both tracks (and Voyage Voyage) were included on her album Free, which was released on May 30, 2008. The album also contains a duet with Spanish singer Soraya Arnelas.

On July 11, 2008, a best-of-album with the title Essential was released. It includes songs which were released by Ryan's former label EMI.

On August 8, 2008 Kate took part in the Polish Sopot Hit Festiwal. During the show she received the Gold album for selling over 10,000 copies of Free in Poland. This is her first certification for this album in Europe.