Rob started his film scoring career with the independent feature Westender. Although a small film, the score was met with some acclaim- "resonant" (Combustible Celluloid), "...unusually rich" (Variety), "vibrant and powerful" (dvdtalk.com). During the film's premiere at the 2003 Seattle International Film Festival, Simonsen met and and befriended esteemed composer Mychael Danna. A year later, both Mychael and Rob had relocated from their respective homes to Los Angeles. Rob soon began working under Mychael in the newly formed Awesome Power Worldwide Inc Studios. Since then he has composed for films ranging from the small independent to the major studio release - working on such titles as Surf's Up, Fracture, Breach, The Nativity Story, Eve and the Fire Horse, Where The Truth Lies, and others, writing for small ensembles up to 80 piece orchestras with full choir.