Brit Halvorsen was born in Gudbrandsdalen, Norway. She graduated from the Royal Danish Academy of Music under the tutelage of Henrik Svitzer, with an exchange program at the Conservatoire National Supérieur Musique et Danse de Lyon under Philippe Bernold, and as a Fulbright scholar at Carnegie Mellon University under Jeanne Baxtresser.

Brit has held positions as alternate principal flutist in the Malmö Symphony Orchestra, principal flutist in the Norwegian Radio Orchestra, and since 2013, as principal flutist in the Royal Danish Orchestra. As a guest musician, she has performed with some of the most prominent Nordic orchestras, including the Oslo Philharmonic Orchestra, the Bergen Philharmonic Orchestra, the Iceland Symphony Orchestra, the Gothenburg Symphony Orchestra, the Swedish Radio Symphony Orchestra, and the Danish National Symphony Orchestra.

In addition to her orchestral career, Brit is an active chamber musician and has been a member of Ensemble Mutatis since 2012.