Goal planning is a central intervention in mental healthcare, focused on changing behaviours and supporting service users to adapt to and manage their illnesses. However, there is currently limited understanding of the types of goals being planned, the experiences of service users and practitioners, or the effectiveness of goal planning as an intervention in mental healthcare, particularly within community pharmacy settings. This doctoral research responds to the gap in literature and knowledge by investigating how goal planning was used in a community pharmacist-led intervention to support the health and wellbeing of service users with a lived experience of severe and persistent mental illnesses (SPMIs). Using the Bridging the Gap between Physical and Mental Illness in Community Pharmacy (PharMIbridge) Randomised Control Trial (RCT) data, this dissertation draws on insights from a pragmatic, mixed method study that addressed the research questions through four Phases, including a systematic literature review, qualitative coding of the PharMIbridge goals, an evaluation of the PharMIbridge goal adherence to the SMART goal model, and qualitative analysis of PharMIbridge service user and pharmacist participant interviews. [...]