Pre-pregnancy overweight/obesity and excessive gestational weight gain (GWG) independently predict negative maternal and child health outcomes. To date, however, interventions that target GWG have not produced lasting improvements in maternal weight or health at 12-months postpartum. Given that interventions solely aimed at addressing GWG may not equip women with the skills needed for postpartum weight management, interventions that address health behaviors over the perinatal period might maximize maternal health in the first postpartum year. Thus, the current study leveraged a sequential multiple assignment randomized trial (SMART) design to evaluate sequences of prenatal (i.e., during pregnancy) and postpartum lifestyle interventions that optimize maternal weight, cardiometabolic health, and psychosocial outcomes at 12-months postpartum. Pregnant women (N = 300; ≤16 weeks pregnant) with overweight/obesity (BMI ≥ 25 kg/m) are being recruited. Women are randomized to intervention or treatment as usual on two occasions: (1) early in pregnancy, and (2) prior to delivery, resulting in four intervention sequences. Intervention during pregnancy is designed to moderate GWG and introduce skills for management of weight as a chronic condition, while intervention in the postpartum period addresses weight loss. The primary outcome is weight at 12-months postpartum and secondary outcomes include variables of cardiometabolic health and psychosocial well-being. Analyses will evaluate the combination of prenatal and postpartum lifestyle interventions that optimizes maternal weight and secondary outcomes at 12-months postpartum. Optimizing the sequence of behavioral interventions to address specific needs during pregnancy and the first postpartum year can maximize intervention potency and mitigate longer-term cardiometabolic health risks for women.