Re: Who is John Harrison (Possible SPOILERS or Insane Babbling)
After reading 13 pages of this thread, I'm not too surprised to see that no one watched Season 4 of Enterprise. It was cancelled after all...but it is still canon, and it is pre-Nero timeline changes.
Peter Weller is playing John Fredrick Paxton, a disciple of Colonel Green and former leader of Terra Prime. Go ahead, check Memory Alpha.
Or you could do a forum search right here for "Paxton" and find that he was brought up and discussed not a little in the thread about the announcement
of Weller's casting, as well as in several other threads between that time and now. Further, you'd find that Paxton also got mentions in threads from well before Weller's involvement was known, including one dated prior to the 2009 movie's release.
"It is my belief that nearly any invented quotation, played with
confidence, stands a good chance to deceive." — Mark Twain