Jack Hyde is a former Commissioning Editor at Seattle Independent Publishing (SIP). He is 32 years old during the events of the series.
As a child, Jack grew up in Detroit, MI. His father died in a bar fight and his mother was an alcoholic, so he was placed into foster care. When Christian's birth mother committed suicide, Christian was placed into the same foster home that Jack was in.
Like Christian, Jack had a violent history as an adolescent, but was able to overcome adversity: he received a scholarship to Princeton University, graduated with a degree in English Literature, and had a successful career. However, Jack still harbored jealousy and resentment towards the Grey family for adopting Christian instead of him.
Ana has an interview with Jack Hyde and Elizabeth Morgan for an internship. Elizabeth expresses doubt about Ana's ability, but Jack argues on her behalf to get her hired. Something about Jack makes Ana feel "unsettled".
Ana starts work at SIP as Jack's personal assistant. Jack is very inappropriate towards her: encroaching on Ana's personal space, repeatedly asking her out for drinks, calling her "honey", etc. This culminates when Jack confronts Ana with her personal email correspondence to Christian and threatens to expose her, unless she provides sexual favors. Ana is able to escape, and Christian has him fired, after all, he owned SIP. When Christian's security team confiscates Jack's work computer, they are disturbed to find that he has been stalking and collecting information on all the members of the Grey family, especially Christian and Carrick.
Jack's obsession with revenge escalates: Christian not only "stole" his opportunity to be adopted by the Greys, he also ruined his career at SIP.
At the close of the book, Jack is spying on Christian's birthday party in a parked car outside Grey Manor. He witnesses Elena's departure, and we find that it was Jack who sabotaged Charlie Tango.
Jack kidnaps Christian's younger sister, Mia, and holds her for a $5 million ransom with the help of his former associate Elizabeth Morgan. Ana manages to foil his plan by shooting Jack on his kneecaps before she fainted, and he is arrested. Christian later finds out that Jack has a history of blackmailing all his female associates by secretly videotaping them while having rough sex with them. He also learns that Mr. Lincoln has paid for Hyde's bail out of spite for Christian since he had an affair with his ex-wife, Elena.