With the increased usage of internal crowdsourcing for ideas, many firms are able to receive feedback from the voluntary collective wisdom with diverse expertise instead of a limited amount of specified experts, resulting in a large amount, diverse and complex input to ideas. Given the so far limited knowledge about it, firms face challenges to fruitfully manage feedback to ideas. Two aspects playing critical roles in the feedback on proposed ideas for innovation are arguably feedback sentiment and its source expertise. This paper aims to explore the roles of feedback sentiment and expertise in internal crowdsourcing for ideas. It does so through an empirical study drawing on data collected from a Swedish multi-national company using internal crowdsourcing for innovation ideas. The investigation explicitly captures the effects of feedback sentiment and source expertise in terms of: 1) positive and negative feedback sentiment; and 2) feedback sentiment in conjunction with expertise of feedback source. The effects of these two dimensions are investigated by performing a logistic regression analysis. Regression results reveal that both feedback sentiment and expertise are potentially impacting ideas in internal crowdsourcing and expertise is a moderator. More specifically, it is found that negative feedback outperforms positive feedback in an overall view, but also that the effects of feedback sentiment are influenced by the expertise of the feedback provider. As one of the first studies to explore the feedback sentiment in conjunction with expertise, this study does not only extend previous knowledge about feedback mechanisms, but also provides practical implications to manage contributors as well as their contributions to internal crowdsourcing of ideas.