Public service motivation (PSM) is a resource that energizes individuals to do good for others and society. However, it is unclear when and how PSM is associated with performance: Does PSM work as a booster to amplify the positive role of job resources for work engagement and performance? Or does PSM help sustain high performance by buffering against experienced cynicism resulting from job demands or the absence of job resources? Using survey data from Denmark, we offer descriptive results suggesting that PSM mainly works to buffer against the detrimental effects of job demands on cynicism and of cynicism on performance.