Norriss is a very manipulative but aggressive man. He started out as a calm professional who is trying to document an infamous actor, but it was all a facade to cover his true nature as a cold-blooded assassin who is willing to kill anyone and oblige to the Mandarin's orders.
After the man previously known as the Mandarin was publicly revealed to be the English actor Trevor Slattery, the real Mandarin ordered his followers to kidnap Slattery and bring the actor to his presence. To this end, Jackson Norriss infiltrated Seagate Prison disguised as documentary maker to interview Slattery. To maintain his cover, he did a lot of research about Slattery's life and interviewed him many times, talking about the role of Aldrich Killian as his employer, the logistics of Killian's plan in creating an amalgam warlord.
On the last day of his interview, Jackson wanted to wrap out his film asking about the real Trevor Slattery, bringing him documents about his past, such as a photograph with his mother when he was a kid, and his role as a main character in a rejected TV pilot. When Norriss asked about the possibility that the Ten Rings or the Mandarin himself could be angered by his portrayal, Slattery was surprised to learn that the terrorists were real, as he previously thought that they were another aspect of the role A.I.M. created for him.
Revealing His True Colors
While relating the history of the Mandarin, Norriss retrieved a handgun he had concealed inside his camera, immediately killing the guards. Herman (another inmate of the prison and Slattery's unofficial butler who accompanied him during the interview) attacked Norriss, but the latter just killed Herman by stabbing him in the neck, much to Slattery's shock.
An angry Slattery picked one of the dead guards' guns and was able to hold Norriss at gunpoint, intending to kill him in revenge for Herman's death. Unfortunately, Norriss disarmed Slattery, revealing that he was sent to break Slattery out of prison and take him to the presence of the real Mandarin for questioning, much to Slattery's confusion.
It's currently unknown of what happened to Jackson Norriss afterwards.