Healthcare professionals have an important role in advocating for the adoption of a brain-healthy lifestyle for optimal multiple sclerosis (MS) care. Nonetheless, studies to date have mainly focussed on the consumer perspective. Herein, we aimed to explore the current practices of how healthcare professionals support protective, lifestyle-related behaviour changes to optimise brain health among people living with MS (plwMS), and their perspectives of professional roles. Australian healthcare professionals were recruited via study advertisements, purposive and snowball sampling, to participate in an online, semi-structured and audio-recorded interview. Clinicians were eligible if they had a minimum of a tertiary Bachelor's degree and 12-months experience working with plwMS, access to the Internet and sufficient time to participant. An inductive, data-driven form of reflexive thematic analysis was undertaken before thematic categorisation of the quotes from transcripts. Data analysis was guided by the methods of Braun and Clark and the study's underpinnings drew on the constructs of the Social Cognitive Theory (SCT). Six physicians, 10 MS nurses, 18 allied health professionals, one exercise therapist and one alternative therapist were interviewed. Three primary themes encompassing the perceived role of healthcare professionals in supporting a brain-healthy lifestyle were identified: (1) the empowering role, (2) collaborative role and (3) communicative role. External factors/forces including time constraints, professional expertise, training and skill set, power dynamics, consumer readiness, health literacy, self-efficacy and motivation are at play, and affect how/when healthcare professionals may support behaviour change to optimise lifelong brain health for plwMS. Healthcare professionals recognise their critical role in encouraging and supporting the adoption of a brain-healthy lifestyle to optimise lifelong brain health for plwMS. However, discord is evident when they underestimate the complexity of translating knowledge of lifestyle-related behaviour change(s) into action. Greater awareness must be made in recognising and addressing the bidirectionality of external factors such as those in the SCT, that may influence how behaviour change occurs. Healthcare professionals volunteered to be interviewed as part of the data collection phase of this study.