Abstract
Salespeople operate in environments that demand both competition and cooperation, yet their dispositional tendencies toward each may vary. While practitioners emphasize the importance of balancing trait competitiveness and cooperativeness, academic research has largely examined them in isolation. Drawing on Job Demands-Resources Theory and Achievement Goal Theory, we conceptualize competitive–cooperative trait balance (CCTB) as a personal resource and examine its effect on salesperson performance. We also test two boundary conditions: supportive leadership (a job resource) and role ambiguity (a job demand). Using mixed-effects modeling, we analyze survey data from 215 inside sales professionals at a B2B financial services company, with survey responses matched to objective performance metrics from company records. Results show that CCTB positively predicts objectively measured salesperson performance; supportive leadership strengthens this effect, while role ambiguity weakens it. To extend these findings, a follow-up qualitative study was conducted with sales managers and sales executives to better understand the mechanisms linking CCTB to performance. Together, these findings contribute to theory by positioning trait balance as a performance-relevant construct and offer managerial insight for hiring and development practices.