This thesis is about the role of media discourse in shaping the political identities of those who want to be heard in public. The ways in which people are able to speak, know, and feel in political situations have important implications for how we conceive of the possibilities to be engaged in contemporary democracy. This thesis offer four empirical studies of how political identities are constructed through journalism and social networking services in cases in which people have decided to make their voices heard. Identities constructed through mediated participation have important implications for how we understand the possibilities to act politically in public, a public that that is characterized as having a multifarious media ecology. Methodologically as well as theoretically it is bound together by a discursive approach to political identities, which means that it is at the discursive level of mediation that identities are analysed as a means to open up for discussions about the limits and constraints of what it means to be political today, what kind and now the media facilitate political engagement. Empirically it analyses print and radio journalism as well as emotional tweets and Twitter profiles to map out ways in which political identities are constructed in activist participation in and through the media. The four different studies contribute to discussions around what it is to be knowledgeable, emotional, subjective and able when you are communicating politics in media discourse. One of the main contribution is that political identities in the media are precarious and that research need to be careful about making too simplistic assumptions about those who make their voices heard in public or what they need to become in undertaking this, and there is a necessary precarious quality to becoming or emerging political in the media, which poses important challenges for social scientific studies that wishes to understand what and who those who act politically through the media.