Bernstein was a larger-than-life figure on stage as conductor, composer, pianist, and media persona, and off stage, too, in his physicality, sociality, charisma, and sensuous engagement with the world. His artistic and celebrity status granted wide berth to Bernstein’s ‘bohemian’ sexual and relationship practices, but he was not exempt from contemporary social expectations and anxieties. Indeed, Bernstein’s life and career illustrate the pivotal effects of twentieth-century sociosexual norms and homophobia on US musical modernism. A gay man in a heterosexual marriage, Bernstein was both a victim and beneficiary, and a sometime agent, of homophobia. In Bernstein the forces of twentieth-century homophobia converged with talent, ambition, and repression, yielding momentous results for his family, intimates, colleagues, and rivals, and for US and international arts and culture. Bernstein’s life and career were fatefully shaped by prevailing social forms and mores, and ultimately his social and cultural influence would contribute to their reshaping.