Criminological literature outlines various roles for public criminologists and reflects on both the form and purpose of public criminology. This article reviews this literature and considers institutional and political activist ethnography as methods through which criminologists can address critique, and better combine social justice research and advocacy work. Such methodological considerations demonstrate that, for some, 'doing' public criminology means actively engaging in advocacy work alongside research participants and other activists. Examples and reflections from the author's own work with the criminal justice voluntary sector (CJVS) in Canada demonstrate that a public criminology informed by institutional and political activist ethnography is especially important if we want to: (i) better understand the role of the sector in supporting people with criminal records; and (ii) strengthen the relationship between academics, policymakers, advocates, practitioners, and people with lived experience of criminalisation and punishment.