Lewis launched a career as a solo singer and musician, leading a group called Juliette and the Licks until 2009. After splitting with the Licks, she has formed a new band called The New Romantiques, with whom she has recorded a new album entitled Terra Incognita.[

Lewis features on the track "Bad Brother" by the band The Infidels, from The Crow: Salvation Soundtrack album, which was released on April 2000. She is working with rock songwriter Linda Perry, among others. Lewis has also appeared on three tracks by Electronic Music group The Prodigy's 2004 CD Always Outnumbered, Never Outgunned ("Spitfire", "Get Up Get Off", and "Hot Ride"). In 2006, Blender magazine included her in their hottest women of rock music list while saying, "[She] delivered sonically varnished melodic punk replete with purring vocals and lyrics that bash porn, pharmaceutical companies and rotten lovers. (in no particular order)".

In 2009 the Juliette played at the biggest open-air festival in Europe (400.000 - 500.000 rock fans every year) - Przystanek Woodstock in Poland.