Despite the accumulated knowledge of how high-performance work systems (HPWS) at the within-organisation levels function, the literature suffers a paucity of attempts to capture the sources of variability. Meanwhile, research on line managers' HR implementation has excessively emphasised their HR-related competencies. At this juncture, this study establishes the interactive effects of team manager's value and ability fit with espoused HR practices under the varying strength of climate for HR implementation. It proposes such dynamics as antecedents to actual HPWS in the organisation. The analyses demonstrated that team managers' value fit consistently impacts implementation behaviours, and their ability fit takes effect when it is accompanied by a high level of value fit. Most conspicuously, climate for HR implementation was found to substitute for effects of person-HRM fit dimensions. Hence, the study articulates further what drives team managers' HR involvement, thereby unravelling intricacies inside the black box of the HPWS-performance relationship.