noun-modifying (irregular), noun
Used as a title or role for the person in charge of a team, section, or project. Often appears in compounds like チーフディレクター or as a standalone noun.
He serves as the chief of the editorial department.
He was appointed chief of the project.
As chief designer, she launched a new brand.
She was appointed chief of the new project.
I consulted the chief of the design department.
部長 is a specific corporate title for the head of a department, while チーフ is a looser, more informal term that can apply to any small team or project.
チーフ is a loanword for 'chief', typically used in job titles, whereas ヘッド is a broader term that can also refer to the top or functional part of an object.
チーフ is used especially for a chief or person in charge in a workplace setting, while キャップ leans more toward a team captain or reporting group head.
Borrowed from English 'chief'.