Budgeting is among the executive's most important powers in a separated political system. The extent to which executive budget proposals are adopted by the legislature is an important measure of the executive's political success. Scholarly literature on budgeting has emphasized how budgets are created but study of executive budget success and its causes is relatively rare. This work seeks to better understand success and the reasons it is achieved through an analysis of the 50 American states for a complete budget cycle. This approach advances the study of budget success by using multiple methods, including measuring success by major issue as well as agency budgets. A survey of budget participants revealed that governors were more successful with partisan support in the legislature, early in their terms, and in a biennial budget cycle. Respondents rated economic conditions, clearly stating and advocating an agenda, and offering popular issues the most important factors contributing to executive budget success. Quantitative analyses revealed that governors were more likely to achieve budget goals with a less professional legislature, legislative term limits, party support in the legislature, biennial budgeting, popular support, and earlier in their terms. Taken together, all analyses suggest that the most important factor in executive budget success is the time in service, followed by partisan support in the legislature, an institutionally weak legislature, biennial budgets, popular support, control over a strong executive budget office, a weak economy, and when proposing large budget increases.