He earned a promotion to department head due to his outstanding performance.

promotion 是名词，来自动词 promote（提升、晋升），指"职位或等级的提升"。在职场语境中特指"升职"。 department head 是由 department（部门）和 head（负责人）组成的复合名词，指"部门主管"或"部门负责人"。