Big Jack is an alter-ego trolls gave Ghost after his return to True Capitalist Radio. The name was likely taken from an Atlanta public access TV host, Jack Jersawitz, a communist that gained notoriety from a series of prank calls to his TV show in the 1990's.
Shortly after Ghost's return, a couple of troll callers (mostly coming from the 712 area code) have been repeatedly calling into TCR asking if he was "Big Jack". Ghost previously brushed off the questions until he was being chain-called with that question during Radio Graffiti on Episode 233.
Jersawitz died in 2012 at the age of 78, thus making allegations that he & Ghost being the same person debunked.
Not long after its inception, listeners began to complain that it was a forced meme. Ghost caught on with this, chastising callers who attempted to call him Jack, especially after Tub Guy made a speech directed at the Tinychat community criticizing the poor quality of calls since the Return. As a result, Big Jack calls are now considered newfaggotry and have about entirely stopped occuring.