Abstract: Approach crafting is employees’ behaviors to adjust their cognition, relationships, tasks, resources or demands to create favorable job characteristics and positive psychological state. It is a kind of extending job crafting behavior. Despite the burgeoning evidence of the positive outcomes of approach crafting, some empirical studies still confirm its dysfunctional consequences. Therefore, the controversial conclusions about approach crafting as found in prior researches indicate that more nuanced examinations should be conducted. To gain more insights, based on self-efficacy theory, the current study investigates the potential dysfunction of approach crafting and proposes a nonlinear relationship between approach crafting and task performance. In particular, this study tests the too-much-of-a-good-thing effect (inverted U-shape relation) between approach crafting and task performance, as well as the mediating role of self-efficacy and the boundary condition of task interdependence. Data were collected from 316 employees, using a two-stage matching survey method to avoid the possible response bias. All the participants are full-time employees, and are employed in different occupations including accountants, human resource specialists, construction managers, doctors and nurses which all having a certain level of flexibility. At time 1, approach crafting, task interdependence, and control variables (gender, age, education, and working years) were measured and 452 completed surveys were returned. At time 2, self-efficacy and task performance were measured by sending WeChat messages, e-mails and paper surveys to the respondents at time 1. After deleting the invalid forms, a total of 316 effective surveys were retained. The Cronbach’ alpha for the scales of approach crafting, self-efficacy, task interdependence, and task performance was .90, .89, .81, .84 (all greater than .80). This study used hierarchical regression analysis and bootstrap method to test hypotheses by applying SPSS 22.0 and Amos 23.0. The results show that after the influence of fixed control variables, there is a too-much-of-a-good-thing effect between approach crafting and task performance, whereby positive phenomena reach inflection points at which their effects turn negative. Self-efficacy is also curvilinearly related to task performance such that self-efficacy shows initial positive effects, then inflects toward negative effects at higher levels and plays an important mediating effect in the inverted U-shaped relationship between approach crafting and task performance. In addition, the inverted U-shaped relationship between approach crafting and task performance is moderated by task interdependence, such that it is more significant when the task interdependence was lower, and is more likely to be linear when the task interdependence was higher, that is, the inverted U-shaped relationship could be alleviated to some extent by task interdependence. Taken collectively, approach crafting can make individuals perceive more self-efficacy, and thus help to improve task performance. However, its positive effects will stop and turn to dysfunctional as individuals engage in more approach crafting. Furthermore, approach crafting is a contextually embedded phenomenon and task interdependence negatively moderates the relationship between approach crafting and task performance. Accordingly, the study gives answer to the question “Does approach crafting always benefit?”: approach crafting is not inherently positive and there are some boundary conditions influencing its effects. The conclusion is consistent with the too-much-of-a-good-thing effect, which indicates that the positive relation could reach inflection points after which the relation would turn asymptotic and often negative, resulting in an overall pattern of an inverted U-shape. This study further developed and added empirical evidence for a more comprehensive understanding of the effects of approach crafting. Moreover, the conclusions that approach crafting does not constantly benefit and some organizational contextual factor plays a moderating role indicate that managers should take several measures to guide or manage employees’ crafting activities to maximize the positive effects and minimize the negative effects, such as inspiring team crafting and implementing job crafting intervention.