Between 2002 and 2004, Jernberg studied jazz at Fridhems Folk High School. Later she studied for Per Mårtensson and Henrik Strindberg at The Gotland School of Music Composition. In 2008, she received the Royal Swedish Academy of Music's jazz award.
Jernberg is also working on the contemporary classical music scene, in which she serves as both singer and composer. As a singer she has premiered pieces by composers such as Lars Bröndum. She was a soloist with Norrbotten NEO when they performed Arnold Schönberg's Pierrot Lunaire. Jernberg has composed for several established ensembles such as Duo ego and Norrbotten NEO.
- 2007 - paavo (with Paavo) - Apart Records APCD008
- 2009 - Crochet (with Lene Grenager) - Olof Bright OBCD25 
- 2010 - Canço del Paó (with Paavo) - Found You Recordings – FYR013
- 2013 - Exit! (with Fire! Orchestra) - Rune Grammofon RCD 2138
- 2014 - Enter (with Fire! Orchestra) - Rune Grammofon RCD 2158