Parental mental illness is a major international public health concern given its implications for whole families, including children. Family-focused practice (FFP), an approach that emphasises a “whole-family” approach to care, provides an opportunity to mitigate the significant risks associated with parental mental health difficulties. The positive benefits associated with FFP have led to a shift in policy and practice towards prioritising FFP within adult mental health services. However, evidence suggests that FFP remains scarce and is not routine. Research has identified the important role of practitioners in facilitating FFP. The current review identified, synthesised and appraised the international qualitative literature examining adult mental health practitioners’ implementation experiences of FFP. It aimed to provide an evidence-informed account of practitioner experiences of FFP delivery and to identify key recommendations to enhance future FFP outcomes in AMHS. Ovid Medline, PsycInfo, CINAHL plus, EMBASE and Web of Science Core Collection were searched systematically, in line with PRISMA guidance, up to January 2022. The Critical Appraisal Skills Programme (CASP) was used to undertake the quality appraisal prior to a thematic synthesis being conducted. The review was registered on PROSPERO. Nineteen papers, spanning 17 years of research with 469 practitioners, were included. Three main themes and 14 subthemes were developed, representing different aspects of practitioner experiences of FFP delivery. Practitioners’ approach to FFP was variable and influenced by their beliefs about FFP, perceived roles and responsibilities, competence, service setting, and personal parenting status. Practitioners engaged in a balancing act to maintain a dual focus on their service-users and their children, to navigate powerful emotions, and consider multiple perspectives in a biomedical organisational structure that advocates individualised treatment. Although working together unified teams, a greater need for external interagency collaboration was identified. The use of strength-based approaches with clients and dedicated staff resources, within clear guidelines and frameworks, was reported to be necessary to maximise FFP delivery. This review proposes a complex FFP dynamic whereby practitioners engage in a constant balancing act between FFP stakeholders to achieve meaningful FFP outcomes for service-users and their families. Service recommendations are provided.