This paper extends prior research to examine the managerial ownership influences on firm performance through the choices of capital structures by using a new sample of S&P 500 firm in 2005. The empirical results of OLS regressions replicate the nonlinear relationship between managerial ownership and firm value. However, we found that the turning points had moved up in our sample compared with previous papers, which implies that the managerial control for pursuing self-interest, and the alignment of interests between managers and other shareholders can only be achieved now by management holding more ownership in a firm than that found in the previous studies. Managerial ownership also drives the capital structure as a nonlinear shape, but with a direction opposite to the shape of firm value. The results of simultaneous regressions suggest that managerial ownership affects capital structure, which in turn affects firm value. Capital structure is endogenously determined by both firm value and managerial ownership; while managerial ownership is not endogenously determined by the other two variables.