Choral singing has characterised music in Irish primary schools for over 100 years as the dominant musical activity and while current government policy advocates for the creative potential of the arts in schools, music as a curricular subject at primary level continues to encounter many challenges. Established in 1985, the National Children’s Choir (NCC) is a choral singing programme for senior primary school children, typically aged 9-12 years in the Republic of Ireland. Offered biennially, the programme involves teachers teaching their classes an extensive collection of songs and then sharing rehearsals and concerts with neighbouring, participating schools. The choral experience is characterised by a challenging repertoire, a range of musical genres, and delivery of the programme by primary school teachers in their classrooms or schools. The current study explores the concept of teacher participation in the NCC pondering: What is the nature and significance of teacher participation? The study is framed within hermeneutic phenomenology and was conducted across three phases, beginning with preliminary data collection and document analysis, followed by an exploratory phase with teachers and principals from four schools, and finally drawing on in-depth interviews with six participating teachers. The qualitative data is complemented by documentary material and statistical data which locate the NCC in its historical and contemporary context. Bourdieu’s (1977, 1986, 1990) socio-cultural concepts, together with Engeström’s (1999, 2001) activity theory are employed to frame and critique interpretations and meanings of teacher participation. Findings indicate that teacher participation in the NCC is a multi-dimensional construct, resulting in multiple outcomes across the domains of teaching and learning, identity, power, capital, and transformation. The data suggests that the nature of teacher participation is broadly positive, where teachers’ musical and professional capital and personal identities are valued and enriched in the habitus of participation. However, the hierarchical structures and narrow aims of the NCC suggest the maintenance of a homogenous, replicative vision of musical experience, inconsistent with contemporary music education research and policy narratives. The findings also suggest ambiguity among participants towards considerations of more collaborative, culturally responsive approaches to music education and the musical repertoire. More broadly, the study points to a need to re-examine the purpose of choral music education in primary schools and the role of external arts organisations, such as the NCC, in curricular provision. Given the current focus on curriculum redevelopment at national level, the study provides an opportunity to critique the NCC within the wider primary school curriculum vision and reimagine its place within music education in the 21st century primary school.