Aims and objectives To explore caregivers’ lived experience of reading slight movements of a child with severe brain injury. Background Despite increased need, the development of individual care for children with severe brain injuries has been prevented by their severe physical state and the poor reproducibility of their movements. In addition to a lack of evidence on the motor characteristics of patients with severe brain injury with multiple disabilities, their own development contributes to increasing variability in their states. Thus, caregivers are compelled to rely on their experiences, which have not been academically explored. Design A qualitative study based on van Manen's method of hermeneutic phenomenology. Methods Data were obtained through twenty‐one 3‐hr observation sessions and five 15‐ to 45‐min group interviews. We observed a child (called AK) with severe brain injury and his 61 caregivers, and conducted group interviews with 28 caregivers. We focused on caregivers’ experiences of reading AK's slight movements. The data were interpreted based on van Manen's hermeneutic phenomenological approach. Results Four themes emerged as caregivers’ experience in trying to read AK's slight movements. By considering “AK's physical state and his slight movements” and discovering “caregivers’ ‘sense of uncertainty’ about AK's slight movements,” caregivers could decipher “AK's multiple slight movements.” “Sharing” was found as a necessary aspect of these other three themes of reading AK's slight movements. Conclusions We presented caregivers’ experiences as related to these four themes in their efforts to read the slight movements of AK. Due to AK's slight movements with poor reproducibility, “sharing” was necessary to read AK's slight movements, as it exposes caregivers’ lived experience to the interpretation of multiple caregivers. Relevance to clinical practice These four themes may be useful for assessing, guiding and promoting caregivers’ use of sharing when reading the slight movements of children with severe brain injury.