This paper uses social movement theory and strategic interactions perspective to examine social movement organizations’ use of a diverse set of tactics in their interactions with local communities, firms, and facilities. Using unique, geocoded data on 527 environmental movement organizations’ (EMOs) reported interactions and toxic chemical-based environmental indicator data between 2000 and 2015, we examine the effect of EMOs’ strategic activities and collaborative interactions on local environmental performance and the conditions under which these effects are amplified. Extending and complementing existing measures of movement activities, we suggest a new measure using local strategic activities that better captures local activists’ influence on the local environment. Our empirical analysis also demonstrates that EMOs’ collaborative interactions significantly improve local facilities’ environmental performance and that the effect of EMOs’ collaborative interactions is stronger in communities with higher level of disruptive protests in previous years, lending support to the radical flank effect hypothesis. Our findings contribute to social movement theory and organizational theory by demonstrating the material impact of movement organizations’ strategic interactions on local corporate facilities’ environmental actions and by highlighting the manner in which the level of local EMOs’ past contentious engagement may moderate the effects of cooperative engagement.