The Jazz Singer was not the first film to have sound; decades of experiments with recording and synchronisation preceded it. What made it a turning point was that it brought synchronised sound to a wide audience as a commercial success. Shot with Warner Bros.' Vitaphone system, the film was mostly a silent melodrama — but the songs woven through it, and Al Jolson's seemingly improvised line "You ain't heard nothin' yet!", showed audiences that the talking image was now possible.

The impact was swift and disruptive. Within a few years the studios converted entirely to sound ("talkie") production, and the distinctive, pantomime-based language of silent cinema became obsolete almost overnight. The transition triggered a ruthless purge behind the scenes: many silent-era stars whose voices or accents were deemed unsuitable saw their careers end, and cinemas dismissed their resident orchestras.

The Jazz Singer also carries a troubling legacy: Jolson's appearance in blackface inscribes the racist entertainment conventions of the era into the film, and is today its most debated aspect. More a technical and industrial threshold than an artistic masterpiece, the film permanently changed what cinema was — from a silent visual art into a narrative in which sound and music were inseparable.