There is a growing need for firms to acquire knowledge externally, but the process has become increasingly complicated. This article studies the mediating roles of the three process dimensions of organizational learning capacity (OLC), namely, knowledge acquisition, transformation, and application capabilities, in the context of a joint problem solving (JPS) arrangement with external collaborators for new product innovation. They employed the structural equation modelling method and analyse a sample of 331 high‐tech manufacturers in China. Their results supported a conceptual model that shows (i) JPS exerts a positive impact on knowledge acquisition and transformation capabilities; (ii) these two capabilities promote knowledge application capacity; (iii) knowledge acquisition alone, and the combination of application and transformation capabilities, mediate the effect of JPS on both innovation efficacy and efficiency. Knowledge acquisition and application capabilities also jointly mediate the effect of JPS on innovation efficacy. They added to the existing literature by highlighting the need to consider the mediating roles of different OLC dimensions and the external context of JPS for learning capacity acquisition. Our model provides a practical framework for managers to better understand and influence OLC dimensions to improve innovation when engaging in JPS.