This study posits a theoretical framework for understanding the role and value of agency input in presidential legislative policy making. I assert that by employing agency input for policy development, presidents instill their proposals with a degree of bureaucratic objectivity, expertise, process transparency, and agency support, which aids their legislative passage while lowering the extent of changes made to policy substance in the process. To test my hypotheses, I conduct binary and ordered logistic regression analyses using pooled cross-sectional data across twelve administrations from 1949-2010. I find that agency input serves as a key component for increased presidential legislative success.