Crinecerfont (CRENESSITY™) is a corticotropin releasing factor type 1 (CRF1) receptor antagonist developed by Neurocrine Biosciences for the treatment of classic congenital adrenal hyperplasia (CAH) in adult and paediatric patients. In patients with classic CAH, circulating levels of adrenocorticotropic hormone (ACTH), androstenedione and 17-hydroxyprogesterone are elevated, which traditionally has required supraphysiologic doses of glucocorticoids to manage. As a CRF1 receptor antagonist, crinecerfont acts by reducing systemic ACTH secretion to subsequently decrease elevated levels of steroid precursors and adrenal androgens, thereby reducing the dosage of glucocorticoids required to manage androgen levels in patients. This article summarizes the milestones in the development of crinecerfont leading to this first approval as an adjunctive treatment to glucocorticoid replacement to control androgens in adults and paediatric patients aged ≥ 4 years with classic CAH.