The Jargon File (version 4.4.7, 29 Dec 2003):

alpha geek
 n.

    [from animal ethologists' alpha male] The most technically accomplished or
    skillful person in some implied context. ?Ask Larry, he's the alpha geek
    here.?


The Free On-line Dictionary of Computing (30 December 2018):

Alpha Geek

    The head geek or geek's geek.  When no one else knows
   the answer, or several techno-types give conflicting advise,
   or the error message says "consult your administrator" and you
   *are* the administrator, you ask the Alpha Geek.

   (1997-06-25)