Yohanna was born in Copenhagen to Icelandic parents Jón Sverrir Sverrison, an electrical engineer, and Margrét Steinþórsdóttir, a nurse.

[1] Yohanna began her music career in 2000, at the age of nine, after signing with Icelandic record label Hljóðsmiðjan.

The two albums contained mainly covers of international pop songs sung in the Icelandic language, such as "Torn", "Genie in a Bottle", and "I'll Be There".

[1][5] After a six-year break from the music industry, Yohanna returned to the public eye after being confirmed as a competitor in Söngvakeppni Sjónvarpsins 2009, the Icelandic national final for the Eurovision Song Contest 2009, in November 2008.

[8][9][10] After winning Söngvakeppni Sjónvarpsins, Yohanna received the right to represent Iceland at the Eurovision Song Contest 2009, held in Moscow.

[14] After qualifying to the final, Yohanna placed second, receiving 218 points, behind only Alexander Rybak of Norway and the song "Fairytale".

[18] Yohanna achieved her second number-one single in Iceland in 2013, performing the song "Mamma þarf að djamma" with Baggalútur.

[19] Yohanna resided in Iceland until 2012, when she moved to the city of Kongsvinger in Norway in order to be closer to the European continent.