We measured the postural sway of two trombonists as they each recorded multiple performances of two solo pieces in each of three different expressive styles (normal, expressive, non-expressive). We then measured the postural sway of 29 non-trombonist listeners as they moved their arms and body, “air-conducting” the recorded sound as if to draw out the emotion from the performance (Experiment 1), and of the two trombonists as they played along with the same recorded performances (Experiment 2). In both experiments, the velocity of listeners’ postural sway was more like that of the performer than expected by chance. Listeners entrained more to back-and-forth than to side-to-side sway in Experiment 1 and only to back-and-forth sway in Experiment 2. Entrainment was not due entirely to performer and listener both swaying to the musical pulse in the same way. Listeners in Experiment 1 rated performances as more expressive when they entrained more, suggesting that entrainment enhanced their aesthetic experience of the music. The whole body appears to contribute to unpacking the expressive content of musical communication.