Grounding data science in societal impact and real-world problems is core to our mission at the University of Chicago Data Science Institute. We integrate community-centered data science across research and educational programs, with the goal of creating student education and career pathways in social impact data science, while meeting the data and technical needs of our organizational partners working at the frontlines of change. For example, in the Data Science Clinic, students work with real-world clients, including social impact organizations, debating data science ethics and developing critical thinking alongside technical skills. Many collaborations emerge from the 11th Hour Project, for which the DSI serves as a centralized hub for nonprofit grantees in four main impact areas: energy, food and agriculture, human rights, and marine technology. We build long-running partnerships with these organizations that can span across multiple years. Recent examples include the interactive data tool PalmWatch, developed in collaboration with Inclusive Development International, which examines the environmental harm caused by palm oil production in countries around the world; and the Grocery Gap Atlas, in partnership with RAFI-USA, a tool that visualizes inequities in food access and corporate concentration in the grocery market at the census tract-level nationwide. Highlighting these projects as case studies, we will discuss why partnerships with social impact organizations are important to data science researchers and our communities, and what makes a successful data science project partnership.