This dissertation explores the compositions of songwriter Harold Arlen, viewing them as musical portraits of the immigrant experience and the racial politics of the United States in the early part of the twentieth century. This approach reveals how Arlen’s upbringing in a racially diverse neighborhood in Buffalo, New York, where Jewish American immigrants and African Americans formed the core of the community, as well as his early years playing in jazz bands and his tenure at the Cotton Club, left a permanent and indelible mark on his compositional style. I trace the influence of African American popular music on his compositional approach, structure, and style. In doing so, this dissertation adds a more nuanced view to narratives about Jewish American songwriters’ use of jazz and blues in Tin Pan Alley song by demonstrating their specific application in the works of one composer. In addition to musical function, the personal and cultural implication of jazz elements in Arlen’s music are also explored.