Healthcare professionals’ innovative work behavior (IWB) plays a key role in the development and implementation of innovative solutions in hospitals. However, relevant antecedents of IWB have not been fully captured to date. This study empirically examines the relationships between proactive personality, collaborative competence, innovation climate, and IWB. Hypotheses were tested using a sample of 442 chief physicians from 380 German hospitals. The results indicate a positive and significant influence of proactive personality, collaborative competence, and innovation climate on IWB, with collaborative competence having a stronger influence on IWB than innovation climate. Managers should note that important resources for IWB are accessible through a variety of actors and relationships. To leverage these resources and thus promote IWB, more emphasis should be placed on an employee’s network.