This is a Phase III, multicentre, randomised, double-blind, placebo-controlled, parallel-group study to evaluate the safety, tolerability, and efficacy of baxdrostat versus placebo, on the reduction of Seated Blood Pressure (SBP) and unsuppression of Plasma Renin Activity (PRA) in approximately 180 participants ≥ 18 years of age with Primary Aldosteronism (PA), with or without prior treatment with Mineralocorticoid Receptor Antagonists (MRAs) or potassium-sparing diuretics. Baxdrostat (or placebo) will be administered once daily, up-titrated after 2 weeks to based on clinical response and tolerability. The study is planned to be conducted globally in approximately 90 study centres and approximately 12 countries.