This article explores narratives of professional social workers tasked with undertaking the formal para-legal role of Best Interests Assessor under the Deprivation of Liberty Safeguards (DoLS) scheme. Wholesale reform of this practice has been debated in recent years and legislative changes have passed through Parliament—the Liberty Protection Safeguards (LPS). The process and debate preceding this change were, however, marked by a relative marginalisation of accounts and critical opinions of Best Interests Assessors (BIAs) themselves. Semi-structured interviews were conducted with a sample group of BIAs from a variety of social work teams within a single Local Authority. These accounts are explored using a thematic analysis underpinned by Ritzer’s McDonaldization theory and Sayer’s work on Contributive Justice. The work considers the professional identities of the BIAs within and beyond their employing organisation in association with social justice and human rights. Barriers and supports to practice are considered in relation to the organisational, technological and legal contexts of assessment work under the DoLS. The study holds relevance for social workers and organisations in contemplating the transition to LPS and workforce conversions to the Approved Mental Capacity Professional.