This study investigates the effect of smallholders’ personality traits on their land rental market decisions. We develop a conceptual framework and show that these internal factors could affect smallholders’ land rental market participation beyond institutional and socio-demographic factors. Our empirical analysis is based on a survey of 2119 rural households collected in the North China Plain. We find that smallholders with a higher level of openness are more active in participating in the farmland rental market. Moreover, internal locus of control plays a significant role in explaining smallholders’ land renting behavior. We further show that need for achievement mediates the link between internal locus of control and smallholder’s intention to rent land, indicating that fostering a higher level of internal locus of control—and subsequently achievement desire—could play an important role in promoting smallholders’ land-renting behavior. More generally, our results imply that taking rural smallholders’ personality traits into account in designing land rental policies may increase the effectiveness of policies aimed at promoting land rental market participation among smallholders and incubating crop farm scale enlargement in rural China.