This paper presents an exploratory investigation of the manufacturing/marketing (hereafter M/M) interface. Drawing on the literature and prior empirical work in M/M strategies, we propose a path model for assessing the mediating impact of the M/M interface harmony—the functions’ ability to work together—on M/M morale and business performance. Using two convenience samples of executives, we empirically test the direct and indirect influence of predisposing factors (antecedents) and performance outcomes (consequences) that are expected theoretically to influence or be influenced by M/M interface harmony. We find that 11 of the 13 hypothesized direct effects are significant at the 0.012 level or below; and attesting to the mediating influence of the M/M ability to work together, 11 of the 12 indirect effects were significant at the 0.02 level or below. Increasing the emphasis on the importance of marketing or manufacturing, or both, improves the ability of both functions to work harmoniously, which in turn impacts M/M morale. Interfunctional harmony appears to have a stronger influence on each function’s morale than the importance attached to that function, ceteris paribus. Contrary to conventional wisdom, the study provides insight on the distinctive roles whereby marketing and manufacturing functions influence performance. Marketing acts to improve competitive position and profitability through the mediating influence of M/M interface harmony and improved marketing morale. However, manufacturing morale was not shown to be a significant factor impacting performance. Rather, emphasis on manufacturing impacts competitive position directly, as indicated by the resource-based view of manufacturing strategy. This exploratory study provides new empirical evidence that the M/M interface harmony, as expressed by the functions’ ability to work together, matters significantly to business outcomes directly and indirectly.