In response to [research output] _The professor might have his or her name on plenty of papers, but never as a first author. Presumably, the papers will look good on the postdocs' and PhD students' CV, not so much on the professor's. Is that the case?_ 

No. Being senior/last author on a paper is valuable, often showing who is the main supervisor [in non-alphabetic author order fields]. Being supervisor of successful PhD's and postdocs is a good thing of course. 

Only having papers as middle author, however, can create the impression that you are someone who is mainly helping others, but not really doing or leading anything yourself.