Acker's previous professional position was Reference Assistant at the Newberry Library.

Acker's MLA service includes membership in the:

     Online Reference Services Committee, 1985-1993 (chairperson 1986-92)
     Subcommittee on Reproduction of MLA Publications, 1993-1998
       (chairperson 1993-1998)

At the 1995 annual conference, Acker presented "Keeping Current with Music Interactive Multimedia" at the Video Roundtable session.

Acker is also very active in the Midwest Chapter of MLA, giving a number of presentations, including "Searching the Internet for Music Reference Service" at the 1997 chapter meeting. Committee memberships include:

     Public Services Committee, 1987-1996
     Chapter Website Committee, 1997-present
     1999 Local Arrangements Committee, chair
     1999 Program Committee

He is also a member of the Music OCLC Users Group and has given presentations on EPIC and Worldcat at the 1991 and 1998 meetings, respectively.