BEWARE OF SPOILERS. Due to the nature of the show, with its many Walking Spoiler characters, twists, and turns, the only spoilers whited out are those for the current season "24: Live Another Day". Proceed with caution!
The leader of a group of anti-government hackers who specialize in leaking classified documents.
- Ambiguously Evil: From the beginning, he's a shady character who's hard to predict.
- Bait-and-Switch Boss: After Margot Al-Harazi's death, he appears set to become the true Big Bad... until he gets killed by Cheng Zhi.
- Big Bad Wannabe: Cross overestimates himself, thinking he can betray the Chinese and Navarro. He succeeds with Navarro, but it becomes very clear that he's utterly out of his depth: he wasn't even working for the Chinese government like he thought, he was working for rogue agent Cheng Zhi.
- Boom, Headshot!: How Cheng Zhi has him disposed of.
- Character Death: Cheng Zhi shoots him in the head.
- Face Death with Dignity: Upon realizing that he isn't going to get out of the ordeal with Cheng Zhi and his men alive, he apologizes to Chloe for withholding information from her and calmly waits for Cheng to finish him off.
- Guttural Growler: As per Michael Wincott, who's practically a professional Guttural Growler.
- HeelFace Revolving Door: Goes back-and-forth between helping Jack and hindering him. The revelation that Steve Navarro is taking orders from him settles Adrian as a Heel.
- Hollywood Hacking: He's very good at this.
- Knight Templar: His actions are sympathetic enough to get Chloe working for him, but he gives no thought at all to the innocent people who'll be hurt in the process.
- Lean and Mean: He's hardly a nice guy, and very gaunt.
- No Celebrities Were Harmed: The show barely tries to hide that he's a take on Julian Assange.
- Token Evil Teammate: As one of Jack's allies helping him stop Margot.
- Well-Intentioned Extremist: Cross genuinely wants to expose the failures and crimes of governments, but he uses increasingly questionable methods.
- You Have Outlived Your Usefulness: Adrian finds himself on both ends of this trope in the same episode when he abandons Steve Navarro to be apprehended by the CIA and is then killed by his Chinese backer, Cheng Zhi.