A competitive business environment demands joint NPD as a form of supplier integration with suppliers. While the joint NPD allows buyers to cooperate with the suppliers’ engineers without formality and constraint, it could cause unfavorable monitoring/controlling behaviors of the supplier salespeople as traditional gatekeepers in inter-organizational collaboration. Thus, the joint NPD success depends on whether the supplier’s salesperson serves as a facilitator or obstructor to the collaboration. Drawing from information processing theory, we explore how a salesperson’s behaviors moderate the effects of the joint NPD on supplier performance to understand the true impact of SI for NPD on its outcomes.