In the Supreme Court, it is common to hear attorneys general and solicitors general addressed as "General."  Personally, I think that is silly, one issue on which I agree with Janet Reno.

There is, however one real general in the room.  That is the Clerk of the Court, Maj. Gen. William Suter (US Army, Ret.).  Amy Howe has this post at SCOTUSblog noting General Suter's 20th anniversary as the clerk.