Growing up in New York City, Mosseri and friend David Baldwin started making music together as preteens. During their high school years, they had rehearsal space next door to the Strokes. Mosseri went on to study film scoring at the Berklee College of Music in Boston, then later reunited with Baldwin to form the indie rock band the Dig. As co-frontmen, Mosseri and Baldwin led the Dig through a series of eclectic albums and EPs during the front half of the 2010s, merging bright synth pop with jangling guitars, psychedelia, and hazy indie pop. In 2016, Mosseri composed his first feature-length film score for the indie comedy How to Tell You're a Douchebag. Meanwhile, the Dig continued to tour and record, releasing the 2017 album Bloodshot Tokyo and a pair of 2018 EPs, Moonlight Baby and Afternoon with Caroline.
Mosseri's profile as a composer rose with the critical success of the 2019 film The Last Black Man in San Francisco. The following year, he composed the score for Miranda July's film Kajillionaire as well as the second season of the Amazon series Homecoming. By this point, the Dig had re-formed under the name Human Love and released the 2020 EP Black Void. In early 2021, Mosseri gained even wider recognition as a composer when his score for the acclaimed film Minari was nominated for an Academy Award. During this period, he also began working on new music with composer Kaitlyn Aurelia Smith, a collaboration that resulted in the ethereal I Could Be Your Dog, released by Ghostly International that September. The duo then issued a companion release, I Could Be Your Moon, a further exploration of electronic ambience and vocals that combined with its predecessor to create a full album. ~ Marcy Donelson, Rovi