|First appearance||The Legend of Sleepy Halliwell|
|Last appearance||It's a Bad, Bad, Bad, Bad World (Part Two)|
|Created by||Brad Kern|
|Portrayed by||Gildart Jackson|
He originally pushes for the Elders to allow Leo to marry Piper Halliwell, and even served as the Charmed Ones' lawyer when Barbas tried to have the Charmed Ones' stripped of their powers. However, at some point between the events in "The Legend of Sleepy Halliwell" and "The Courtship of Wyatt's Father", Gideon's attitude toward the couple and their one-year-old son Wyatt Halliwell changes drastically. He fears that Wyatt's vast powers will turn him evil and allow him to become an unstoppable threat. His belief is only strengthened by the arrival of Wyatt's younger brother, Chris from a future where Wyatt is the king of evil and ruthlessly rules over the entire world. With this new "evidence", Gideon decides that the "mistake" of allowing Wyatt's birth has to be corrected for the greater good.
Having gained the sisters' confidence, Gideon uses his position as a friend of the family to get close to Wyatt as he plots to destroy Wyatt. He even hires a team of darklighters to get Leo out of the way.[episodes 2] However, his efforts are slowed often by the very thing that seems to confirm his fears about Wyatt: Chris. The young half witch/whitelighter is determined to find and stop the person or persons responsible for his brother turning evil, causing Gideon to tread lightly around him.
When the Charmed Ones nearly catch on to his plans, his desperation leads him to conspire with demons who run a game show where demons kill witches and steal their powers for their own gain. He has the hosts and their henchmen attack the sisters, Leo and Chris in hopes of leading them off his trail, which works temporarily. Though he threatens the hosts so they won't harm innocents of the Charmed Ones his reckless and ill-thought out scheme leads to the death of an innocent witch.
Through a magic mirror, Gideon communicates with his evil counterpart in a parallel dimension to distract both the good and evil Charmed Ones so that they might kill their Wyatts.[episodes 3] Realizing Gideon is the one after Wyatt, the sisters, Leo and Chris are able to stop him by joining forces with their evil counterparts. In the process, however, they manage to significantly warp the cosmic balance so that their world becomes too good; even minor transgressions result in people having body parts cut off, or even killed.
Gideon realizes that killing Wyatt will be the act of "great evil" necessary to restore the balance between the good and evil worlds. However, the sisters, Leo and Chris soon discover that in Chris' timeline, Gideon took Wyatt away for several weeks in his attempt to kill the boy. While Wyatt was able to fend him off, the trauma of having to constantly defend himself was too much for his young psyche to handle, and turned him evil—thus making Gideon's concerns a self-fulfilling prophecy.
Gideon conspires with Barbas, who uses his powers to distract the sisters and Leo while Gideon kidnaps Wyatt, killing Chris in the process. Grief-stricken by his son's death, Leo tracks Gideon down in the Underworld just as the Elder is about to kill Wyatt. Gideon claims that Wyatt's death is necessary to protect the future. Leo immediately counters that killing a child is never for the greater good, and that Gideon is the real reason the future is threatened. He then savagely electrocutes Gideon—a "great evil" that restored the balance between the good and evil worlds.[episodes 3]
- "The Legend of Sleepy Halliwell". Charmed. Season 6. Episode 14. 2004-02-08. The WB Television Network.
- "The Courtship of Wyatt's Father". Charmed. Season 6. Episode 16. 2004-02-22. The WB Television Network.
- "It's a Bad, Bad, Bad, Bad World (Part 2)". Charmed. Season 6. Episode 23. 2004-05-16. The WB Television Network.