He is portrayed by Peter Mackenzie.
Dirk Armstrong is present at a board meeting of CatCo Worldwide Media in which the company decides how to move on after e-mails from Cat Grant, CEO of the company, have been released by an anonymous hacker. The board comes to the conclusion that Cat should step down should more of her e-mails be released. However, while the board leaves the office Kara overhears Armstrong remarking that everything is going as planned. Realising that Armstrong hired the hacker, Kara and her friends decide to
Lane tells them that Armstrong could be charged for corporate wrongdoing should they be able to present evidence linking him to the hacks. However, she warns them that they could make things much worse should the evidence be too weak. To get evidence on Armstrong, Winn produces a device which would gain him entrance to all of Armstrong's files once it's placed at his computer. James decides to sneak into Armstrong's office to plant the device. To create a distraction, Winn calls Armstrong and tells him that his car is on fire. While Armstrong panics and runs to the elevator, James enters the office. He manages to attach the device, but with her ray vision Kara finds out that Armstrong is returning. Unable to flee in time, James waits for Armstrong to return and acts like he supports the intrigue against Cat. Armstrong claims that while surely no one would want Cat to go, the board would approve James' support should things go down with Cat.
After checking Armstrong's computer, James, Lane and Winn arrive with evidence just in time to stop Cat from announcing her plans to step down. Cat later calls Armstrong to her office and confronts him, revealing that all of his electrical devices are searched by the police as they are speaking. She then orders two security guards to escort Armstrong out of the building, telling them to make sure the press gets enough pictures of Armstrong being dragged outside.
- Armstrong drives a Maserati.