While online news media have shown considerable growth, little is known about how online users’ journalistic role conceptions and perceived credibility of journalistic contents exert influences on their news engagement. Thereby, this study aims to investigate the role of credibility of online news by elucidating its interaction effects on the relationship between journalistic role conceptions and news engagement. Results based on a web-based survey data with the South Korean sample (N = 601) show that the civic facilitating and supporting roles of journalists positively and significantly predict online users’ news engagement. Besides, perceived credibility has a strong association with participants’ news exposure and participatory news use in digital media platforms. On top of this, credibility judgment significantly moderates the strength of the relationship between news users’ perception of journalistic roles and news engagement. We discuss the probable implications of the findings.