Film music has increasingly populated the concert programs in the last twenty years. Yet, the presentation of the film-music repertoire in concerts is a corner of the film–music field that has received little scholarly attention. Archival research combined with the study of audio–visual documents in particular is the key to reconstruct the story of the presentation of film music in concerts. As a case study, I present the findings of the research that I conducted in Boston, U.S.A., in 2010 and 2011. Its aim was to demonstrate John Williams's seminal contribution to the legitimization of film music as a viable concert repertoire during his tenure as conductor of the Boston Pops Orchestra—“America's orchestra”. The results showed very convincingly that John Williams's association with the most trend–setting and visible orchestra in the U.S.A. has been a major force and a seminal influence for the acceptance of film music as a legitimate concert repertoire.