Shepard was born in San Diego, California, in the United States in 1991 to a Norwegian mother and an American father before her family moved to Oslo at a young age.

[5] The project's name Sylvaine was inspired by the word "sylvan" (meaning forest, woods) and the surname of French poet Paul Verlaine.

[5] Shepard self-released her first album Silent Chamber, Noisy Heart in 2014 after writing it in Oslo from late 2012 to early 2013.

[7] The third Sylvaine album Atoms Aligned, Coming Undone was released on 2 November 2018 and was preceded by the singles "Abeyance", "Mørklagt" and "L’Appel Du Vide".

[3] In 2019, Shepard provided guest vocals on the song "L’île des morts" from Alcest's sixth album Spiritual Instinct.