Background: A significant gap remains between the availability of physical activity (PA) evidence-based interventions and their application in real-world settings in policy and practice areas. This study aims to describe highly cited and high altmetrics publications in PA research and explore their impact on PA policy and practice. Methods: Mixed-methods sequential explanatory study including the identification and description of the top highly cited and high altmetrics PA publications from the last 10 years (including study design, population, type of PA study, number of citations, and altmetrics score), and interviews with key informants regarding research dissemination and implications on PA policy and practice. Results: When considering publication type, the most frequent highly cited publications were health consequences (40%, altmetrics = 42%), measurement/trends (23%, altmetrics = 10%), and correlates/determinants (21%, altmetrics = 26%) studies. They were predominantly cross-sectional (50%, altmetrics = 28%), systematic reviews (38%, altmetrics = 18%), and longitudinal studies (8%, altmetrics = 37%). All authors who participated in the interviews agreed that the most important factors in disseminating findings and influencing PA policy and practice were the published peer-reviewed manuscript itself, the reputation of the journal, the communication strategy, and the use of online platforms. Conclusions: To have a real-world influence on PA policy and practice, it is not enough to publish the results in scientific journals and participate in media outreach. To successfully involve policymakers and communities in appropriating the evidence and evaluating the extent to which these findings affect policy and practice outcomes, it is critical to lead co-creation, co-dissemination, advocacy, and capacity building efforts.