La Havas was born in London, England to a Greek father and Jamaican mother. She was raised in Tooting and Streatham, spending the majority of her time with her grandparents, following her parents' separation as a child. La Havas' cites her parents' diverse musical tastes as having the biggest influence on her music. She began singing at seven. Her mother played Jill Scott and Mary j. Blige, while her father, an accomplished multi-instrumentalist, taught her the basics of guitar and piano. Lianne wrote her first song at the age of 11 but did not learn to play the guitar until she was 18 years old. At 18, Lianne began attending Norbury Manor Business and Enterprise College for Girls in Croydon, where she studied art and planned to take her A-Levels in art foundation. However, she left college and decided to pursue a career in music full-time.
While attending sixth-form in Croydon, a friend of La Havas', (who attended the Brit School) introduced her to other musicians who assisted La Havas in the recording of her first demos. Through that same friend, La Havas was also introduced to British singer, Paloma Faith; she later sang backing vocals on tour for Faith. La Havas was co-writer and performer in 'The Paris Parade' alongside Christian Pinchbeck (who designed the artwork for Lost & Found) and also is now part of the duo Elephant (Memphis Industries). They had a short career but it began La Havas' career in commercial music. In 2010, Lianne signed to Warner Bros. Records, spending two years developing her songwriting skills before releasing music publicly.
La Havas made her television debut on October 21, 2011, broadcast of BBC Two's Later, with Jools Holland, a program that also featured Wisconsin folk band Bon Iver. Following her appearance on Later, with Jools Holland, it was announced on October 25, 2011 that La Havas would be the supporting act for Bon Iver's December 2011 North American tour.
La Havas released her debut EP, Lost & Found, on October 12, 2011 on the Labour of Love label and featured Willy Mason on the opening track, No Room For Doubt. That same month, La Havas released a live EP, titled Live in LA, which was made available for free download on her website. La Havas released her third EP titled Forget, on December 30, 2011 on the label Warner Brothers.