Background. Throughout its 25-year history, the United States Department of Veterans Affairs (VA) Quality Enhancement Research Initiative (QUERI) program has been a forerunner in partnering with organizational leaders to improve health care. The Foundations of Evidence-based Policymaking Act of 2018 provided new opportunities for QUERI and other implementation scientists to support federal agency leaders in implementing, evaluating, and reporting on congressionally mandated programs. Although implementation scientists have the skills to support partnered implementation and evaluation, these skills must be adapted for congressionally mandated projects as many scientists have limited experience in policy analysis and the intersection of data informing organizational policy, programs, and practices (i.e., evidence-based policy). Therefore, the aim of this session is to describe a process model for assisting partners in addressing requirements of legislation, and to review policy analysis, planning, and evaluation design tools and processes. Methods. During the conduct of four congressionally mandated projects, our national VA QUERI team developed processes and tools to achieve the goals and aims of our partners and to ensure our collective work and reporting met legislative requirements. Our process model, program planning, and analysis tools were informed by an iterative process of refining and adapting the tools over a period of six years, spanning 2017 to 2023. Findings. Work to support our partners was conducted across three phases: preparation and planning, conducting implementation and evaluation, and developing the congressionally mandated report. The processes and tools we developed within the context of mutually respectful and honest partnerships have been critical to our QUERI center’s success in this area. Discussion. Lessons we learned may help other scientists partnering in VA, or other federal agencies, to plan, conduct, and report on congressionally mandated projects.