Nathan Barr began studying music in Tokyo, Japan at the age of four. He grew up surrounded by eclectic music ranging from Kabuki Theater, to the sounds of his mother performing on the koto and piano, to his father playing the banjo, guitar, and shakuhachi. His interest in music was further influenced by extensive travels around the world, where he experienced music ranging from Bali's Kecak Orchestras to China's Beijing Opera. During the summer of 1993, he toured Italy and Switzerland with the Juilliard Cello Ensemble. Upon graduating from college, he joined the industrial alternative rock group V.A.S.T. (Elektra Records) for a short time, playing guitar and electric cello.

Looking to explore a career in film music, he moved to Los Angeles in 1996, where he met Academy Award-winning film composer Hans Zimmer, who invited him to join him as his assistant. After eight months with Hans, Nathan landed his first feature and struck out on his own and has been working constantly ever since.