Should I use Japanese title for Japanese people instead of English title? I'm in contact with a Japanese student support staff of a Japanese university. Because he is a staff, I don't know how to address him properly: Mr. or Dr. or Prof. However, I know that in Japanese culture, there is only one title for this job: sensei:


  sensei: (for example Sato-sensei)
  This is a title used for teachers, doctors and other people with a higher education and from whom you receive a service or instructions.
  www.japan-guide.com


As a member of the Sinosphere culture, I understand that correct title is important. Also, this would indicate that I'm trying to learn how the culture works, even thought I don't know Japanese.

Should I?
Assuming you are writing in English, I would say 


The expected* way to address university staff (non-faculty) is
generally "Mr" or "Ms" depending on their gender. 
You can call
people who you would call sensei in Japanese by [family name]-Sensei
(note the position of the sensei as after) in English. 
Calling people with doctorates "Dr X" is not generally expected in
    Japan. (Also, many Japanese faculty who are older don't have doctorates due to some vagaries of the system used here).
Similarly, they are much less used to "Professor X" than
    in American contexts. 


I would say (2) is normal in day-to-day conversation, but for many of them writing = Mr / Ms

Separately, if he is truly "support staff," then he is not a sensei within the Japanese system. If he is over the support staff, that might not be true.



*by "expected" I mean the expectation of most Japanese users of English

Source: 1kyu (JPLT N1) and presently living in Japan working at a university