Sweden’s NATO accession has introduced a dual requirement for C2 interoperability within the Armed Forces, combining robust national joint operations with effective multinational integration. This study examines how Swedish operational command is understood and described by actors in the transition from national responsibility under Article 3 to collective defence under Article 5. Drawing on doctrinal analysis and interviews with personnel at strategic, operational, and tactical levels, central tensions between ambition and practice are explored. The findings suggest that interoperability is primarily a cognitive and conceptual integration process rather than a purely technical adaptation. At the same time, operational tempo and freedom of action are described as constrained in relation to unclear roles, mandates, and limited internal coherence. The study suggests that leadership emerges as central for sensemaking and conceptual adaptation, while formal command authority is highlighted as important for maintaining vertical coherence and supporting robust C2 interoperability.