Having been raised in a musical family, Rob Simonsen gravitated towards the piano at an early age. When he was 14, his dad gave him an old Mac SE with a very basic midi programme and he started sequencing, and kept doing that ever since.
After having played in a number of jazz fusion bands, Simonsen began scoring films for friends and later contributed additional music to a number of big film scores, including the score for Life of Pi, which won an Academy Award for Best Original Score. In 2008, Simonsen co-scored 500 Days of Summer with Mychael Danna, which kicked off his career as a film composer. Since then, he has signed with Kraft-Engel and scored numerous films, such as Foxcatcher (2014), Nerve (2016) and The Spectacular Now (2013).
An avid collaborator, Simonsen founded Los Angeles-based artist collective Echo Society in 2013. The collective seeks to create connections within the Los Angeles arts community, while bringing both orchestral and electronic music to new audiences.
In 2019, Simonsen signed to Sony Masterworks as a recording artist and released Reveries, his first album on the label.