This article investigates how implementation collaborations between law enforcement and mental health organizations generate resilience to sustain and adapt themselves in volatile environments. Data come from interviews with practitioners and reviews of media and planning and program documents in four distinct local settings. The study extends understanding of resilience in three ways. First, it examines practices to build interorganizational resilience from different strands of literature—boundary practices that help diverse partners understand and work together across differences, and high reliability practices to sustain joint operations. Second, it identifies four challenges that volatility poses for implementation collaborations and shows that collaborations in different settings can combine the practices in distinct ways to address each challenge. Local conditions thus may matter less for building resilience than how collaborations combine practices. Third, it uncovers a new reflexive practice—collaborative assessment and adjustment—likely to be particularly useful to build resilience in volatile environments. Resilience amid volatility thus may be less a state collaborations achieve than an ongoing process partners cultivate in different ways in response to specific challenges. The article concludes with ideas for future research, including studying challenges of volatility and practices to cultivate interorganizational resilience in additional policy fields.