Lemborexant (DAYVIGO™) is an orally administered, dual orexin receptor (OXR) antagonist that exhibits reversible competitive antagonism at OXR1 and OXR2 (> affinity at OXR2) that was discovered and developed by Eisai Inc. for the treatment of adult patients with insomnia. In December 2019, lemborexant received its first approval (with final interim scheduling) in the USA for the treatment of adult patients with insomnia, characterized by difficulties with sleep onset and/or sleep maintenance. In January 2020, lemborexant also received approval in Japan for the treatment of insomnia. It is also being investigated for the treatment of irregular sleep-wake rhythm disorder (ISWRD) associated with mild to moderate Alzheimer's disease. This article summarizes the milestones in the development of lemborexant leading to its first global approval.