This study investigated whether participation in an ensemble-based music education program was associated with evidence of internal strengths, changes in perceptions of peers, or changes in behavior among incarcerated youth. Participants were 54 adolescents (63% male), held in 2 secure detention facilities, who elected to take part in a 2-week choral residency program. Rates of attendance at residency sessions, completion of the program for school credit, and engagement in musical activities outside of the residency session were high, while the results of a reflection exercise indicated that participants had more positive views of their self-esteem, engagement, and mood when they were engaged in musical activities then when they were not. A series of multilevel models revealed significant reductions in observed antisocial (B = −1.06 (.300), p < .001) and staff-reported externalizing behaviors (B = −9.59 (2.27), p < .001) for the program overall. However, additional modeling results indicated that reductions in antisocial behaviors were concentrated at one facility, B = −1.73 (.387), p < .001, and that at this at this facility participants’ perceptions of their peers were more positive following the program, B = 19.1 (6.26), p = .002. These findings are interpreted from a dynamic systems perspective, with an emphasis how the environmental context of each facility may have fostered or constrained the efficacy of the music program.