Background Anaplastic lymphoma kinase (ALK)‐positive lung cancer has a better long‐term prognosis with ALK‐inhibitor than other lung cancers. However, resistance to ALK‐inhibitors and the control of metastases in the central nervous system (CNS) remain to be a challenge in the management of ALK‐positive lung cancer. Case We present the case of a 23‐year‐old man who developed multiple brain metastases while receiving alectinib treatment for ALK‐positive lung cancer. After 3 months of lorlatinib initiation, brain metastases disappeared, and complete response (CR) was maintained. Conclusion While lorlatinib can be used as first line therapy, this drug may be considered as second line or later option for patients with multiple brain metastases if the patient has already been treated with other ALK‐inhibitors since lorlatinib is thought to have good CNS penetration. This treatment option should be verified by further research.