Mark Karpelès was born and raised in France. He began his involvement in Bitcoin in 2011 when he acquired 88% of Mt. Gox, the Bitcoin exchange located in Tokyo, from its founder Jed McCaleb. Karpelès is a founding member of the Bitcoin Foundation which was created to promote Bitcoin and standardize it, however he later resigned from his place which brought confusion and concern to many.
In February of 2014 Mt. Gox filed for bankruptcy, and Mark Karpelès was subpoenaed to appear in court and provide testimony, but he declined. He was later tried (in absentia) and found guilty of fraud and also admitted to having pirated a server. He was sentenced to a year in jail, which he has yet to serve.
The idea has been brought up that “Dread Pirate Roberts” the person behind Silk Road, is in fact Mark Karpelès (instead of Ross William Ulbricht who is currently in trial over this), however Karpelès has publicly denied the claim.