Today, there is much academic discussion about how journalism and journalists are affected by rapid change and convergence in the work context. Considering the fundamental transformations of the media ecology brought about by digitization and the advent of social media, it has been assumed that journalists are more or less compelled to reinvent their professional role and identity. We know a good deal about how social media is adopted by journalists, mostly through survey and interview studies investigating self-perceptions of identity in terms of norms and values. There are also some case studies, predominantly in the form of (quantitative) content analyses, exploring the (innovative) uses of Twitter. However, we still have little knowledge about how the professional identity of journalists is discursively constructed – how, in specific detail, traditional norms and ideals are discursively reinforced or challenged – in the Twitter flow. With a discourse theoretical and methodological approach, this article aims to contribute to our understanding of the discursive construction of professional identity on Twitter by qualitatively analyzing tweets from the most widely followed journalist in Sweden. The analysis of the most active j-tweeter can yield important clues as to what journalism may be in the process of becoming. The article identifies discourses that (1) reinforce the watchdog identity, (2) challenge the watchdog identity, (3) reinforce the disseminator/explicator identity, and (4) reinforce transparency but challenge professional identity. It concludes that the reinvented journalistic identity includes discursive processes that both shape and are shaped by Twitter in a dialectical relationship.