Exposure to metals is associated with an increased risk of various diseases, including hypertension and chronic kidney disease (CKD). However, the joint effects of co-exposure to multiple metals on these diseases remain poorly understood. We conducted a cross-sectional study involving 4776 adults from the National Health and Nutrition Examination Survey 2011 to 2018 to examine the effects. Five statistical methods were employed to assess the associations of metals with hypertension and CKD risks. Exploratory decomposition analysis was used to estimate the exploratory decomposition effects of blood pressure and renal function indicators. We found a positive correlation between the blood metals mixture and the risks of CKD and hypertension, highlighting that Pb and Cd were the primary contributors. Conversely, the urinary metals mixture exhibited an inverse association, with Ba and Tl identified as the main contributors. Restricted cubic spline analyses revealed complex dose-response relationships between metals and CKD and hypertension risks, including linear, U-shaped, L-shaped, and inverse U-shaped patterns. Exploratory decomposition analysis demonstrated that renal function had exploratory decomposition effects in the metal-hypertension associations, whereas blood pressure had exploratory decomposition effects in the metal-CKD relationships. Our findings suggested that metal exposure was significantly associated with CKD and hypertension risks. Blood pressure and renal function had exploratory decomposition effects in the associations of metals with CKD and hypertension, respectively.