Arnold grew up in almost-rural western Massachusetts, listening to his father’s finger-style guitar and folk music. He described a love of popular music, jazz, rock, musical theatre, and Motown. Originally auditioning for The George Washington University on classical piano, he later studied the upright bass with Herman Burney Jr. In addition to his instructors, fellow students (many of whom are close friends to this day) helped him to learn to play jazz, taking him to jams and hotspots where he got his first gigs. Arnold soon became what CapitalBop described as “…one of the most versatile bassists and side musicians on the D.C. jazz scene.”
Arnold’s band Sea Change was formed in February 2018 in Washington, D.C., when he was asked to lead a band at the Göethe-Institut’s Jazz in the Basement series. His 2020 debut album as a composer, Sea Change, was a finalist for jazz album of the year at the WAMMIE Awards and was named the #4 jazz album of 2020 by local jazz blog CapitalBop. Of his bandmates (Sarah Marie Hughes/saxophone, Federico Gonzalez Pena/piano, Nelson Dougherty/electric guitar, and Keith Butler, Jr./drums), he says he’s drawn to collaborators with their own personality and style, and describes them as “really sensitive and open to feedback, none of them are in a box, you know… It’s like having a family of friends. I feel really lucky that I’ve been able to maintain those connections, so that we can say something really heartfelt.”