The prevention of violent radicalisation in criminal justice settings is a neglected topic especially in the context of restorative justice and positive psychology. Generally, emphasis is given on the youth justice system and young perpetrators, albeit most convicted extremists being adults. This chapter focuses on the implementation of this book’s positive preventive approach with criminal justice professionals who support convicted extremists or adults at risk of engaging in violent radicalisation and extremist acts. The chapter takes a significant step forward for the RJiNEAR model, as it moves it out of the youth resilience space and into adult offending and rehabilitation. The chapter is based on a 2-year project that collected data through primary and secondary research as well as pilots in six European countries. The findings show that the project’s target groups had extremely low levels of knowledge of restorative justice and positive psychology, particularly in relation to preventing violent radicalisation, hate violence and extremism. However, there was appetite in learning, and thus the pilots were generally deemed successful. Moreover, pre- and post-intervention evaluation suggested that the piloted preventive model can render positive results for convicted adult extremists and those at risk of violent radicalisation and hate violence.