Music engagement is complex and is influenced by music training, capacity, preferences, and motivations. A multi-modular self-report instrument (the Music Use and Background Questionnaire, or MUSEBAQ) was developed to measure a diverse set of music engagement constructs. Based on earlier work, a hybrid approach of exploratory and confirmatory analyses was conducted across a series of three independent studies to establish reliability and validity of the modular tool. Module 1 (Musicianship) provides a brief assessment of formal and informal music knowledge and practice. Module 2 (Musical capacity) measures emotional sensitivity to music, listening sophistication, music memory and imagery, and personal commitment to music. Module 3 (Music preferences) captures preferences from six broad genres and utilizes adaptive reasoning to selectively expand subgenres when administered online. Module 4 (Motivations for music use) assesses musical transcendence, emotion regulation, social, and musical identity and expression. The MUSEBAQ offers researchers and practitioners a comprehensive, modular instrument that can be used in whole, or by module as required to capture an individual’s level of engagement with music and to serve as a background questionnaire to measure and interpret the effects of dispositional differences in emotional reactions to music.