Differences between various words for "person in charge"

Question

Particularly I am thinking of 係員, 係官, 担当者, 主任, 主任者, 責任者, and 担任.

I know that 担任 is almost exclusively used for teachers/education but there are examples outside of this (weblio examples: ある仕事を担任する, 1874年兵庫新川開鑿事業担任に任命). Is this more of a deprecated use, or is there some pattern for when this is used in other contexts? Also unlike the other forms I used, it usually doesn't refer to the person in charge, but simply the action, but again, there are exceptions.

係官 seems to be used for government officials that in charge of something.

But the nuances between the rest elude me. Is my understanding of the above correct, and what are the nuances with the others?

Answer 1

• 担当者 is the usual translation for "person in charge". This refers to anyone who can deal with the issue at hand, regardless of their rank. This word is used typically when you want to contact whoever can handle your problem.
• 係員 in modern Japanese is close to "attendant" (or "usher", "clerk"). It refers to a person who wears a uniform and provides assistance to guests at an amusement park, a museum, an airport, a trade show, etc. According to dictionaries, it can mean the same thing as 担当者, but I think this sense is mostly obsolete.
• 主任 is "chief" or "senior staff" (of a section, a division, etc.), someone who is in charge as a leader/chief. Note that 主 means main.
• 責任者 refers to the boss/manager of a shop, a section, etc. It refers to the highest ranked person who takes ultimate responsibility when a critical problem arises.
• 係官 is an uncommon word, but it refers to a 係員 who is also a "官" (government officer). For example, a customs officer can be called a 係官.
• 担任 in modern Japanese almost always refers to a teacher (when used as a noun). 担当 is used outside schools.

For example, a コンサートの担当者 is an office worker who works for the event, knows about the event well, and responds to inquiries from outside the company. A コンサートの責任者 is the top manager/director of the concert. A コンサートの係員 is someone (often a part-timer) who organizes waiting lines or check tickets at the site.

担当 by itself can be used both as a suru-verb and as a noun meaning "person in charge". 者 is a suffix that means "person", so 担当者 works only as a noun. 担当は誰ですか and 担当者は誰ですか mean the same thing. 主任 and 担任 are used primarily as nouns, so 主任者 and 担任者 are redundant and uncommon. 責任 never refers to a person.