Using a life course approach, the Centers for Disease Control and Prevention's Division of Cancer Prevention and Control and the National Association of Chronic Disease Directors co-hosted a 2-day meeting with 15 multidisciplinary experts to consider evidence linking factors in early adulthood to subsequent cancer risk and strategies for putting that evidence into practice to reduce cancer incidence. This paper provides an overview of key themes from those meeting discussions, drawing attention to the influence that early adulthood can have on lifetime cancer risk and potential strategies for intervention during this phase of life. A number of social, behavioral, and environmental factors during early adulthood influence cancer risk, including dietary patterns, physical inactivity, medical conditions (e.g., obesity, diabetes, viral infections), circadian rhythm disruption, chronic stress, and targeted marketing of cancer-causing products (e.g., tobacco, alcohol). Suggestions for translating research into practice are framed in the context of the four strategic directions of the National Prevention Strategy: building healthy and safe community environments; expanding quality preventive services in clinical and community settings; empowering people to make healthy choices; and eliminating health disparities. Promising strategies for prevention among young adults include collaborating with a variety of community sectors as well as mobilizing young adults to serve as advocates for change. Young adults are a heterogeneous demographic group, and targeted efforts are needed to address the unique needs of population subgroups that are often underserved and under-represented in research studies.