Martin Walker (White House Down)

Martin Walker is the secondary antagonist in the 2013 film White House Down. He is the corrupted head of Presidential Detail and was introduced as the film's main antagonist, but this was all a misinformation campaign to conceal the identity of the true main villain.

He is portrayed by James Woods, who is known for portraying Ned Trent, Hades, and Dr. Phillium Benedict.

Biography
A man disguised as a janitor sets off a bomb at the center of the US Capitol building. White House Speaker Eli Raphelson, who was in the Capitol, remains unharmed and is taken to an underground command center with Finnerty, while Vice President of the United States Alvin Hammond (Michael Murphy) is taken aboard Air Force One. The White House is put on lockdown, separating Cale from Emily, who had left the tour group to use the restroom. Meanwhile, mercenaries led by Emil Stenz, who had disguised themselves as video technicians to get inside the White House, start killing off all security officers and take the tour group hostage, but Cale manages to take a gun and escape to go find his daughter. Walker escorts the President and his detail to the Presidential Emergency Operations Center. Once Sawyer gains access, Walker kills his detail, revealing himself to be the real leader and wants vengeance against Sawyer after a botched black ops mission resulted in the death of Walker's son. Cale, who failed to find Emily, kills a mercenary and takes his gun and radio. Overhearing the radio, Cale locates and rescues Sawyer. The authorities then decide to bring in Walker's wife Muriel to talk some sense into her husband, but she instead convinces him to carry on with the plan to avenge their son's death after hearing him justify it, which resulted Muriel to be placed in a federal prison for life.

Walker and Stenz bring in Skip Tyler (Jimmi Simpson) to hack into their defense system, but they still require Sawyer to activate the nuclear football. They locate the remaining chain of command and execute the Secretary of Defense before putting them with the hostages. Emily, while hiding, records a video of the mercenaries and puts in on YouTube before eventually being captured. Cale and Sawyer manage to reach out to the command structure through a satellite phone Sawyer keeps to communicate with his wife and they tell Cale to get the President out through underground tunnels. At the command center, Finnerty uses Emily's video to discover the mercenaries' identities, who used to work for various government agencies. They also discover that Walker has an inoperable tumor, suggesting his involvement to be a suicide mission and that the attack is meant for more dangerous reasons. Cale and Sawyer find the tunnel gate rigged with an explosive and are forced to escape with a presidential limo. After giving chase with Stenz on the White House lawn, Cale and Sawyer get flipped into the White House pool after Cale gets distracted by a mercenary holding Emily at gunpoint. A gunfight erupts which results in an explosion that leaves Sawyer and Cale presumed dead. Hammond is then sworn in as acting President.

When Cale and Sawyer reveal they are still alive, they learn Hammond has ordered an aerial incursion to take back the White House. Knowing the mercenaries have Javelins, Cale tries but fails to stop them from shooting down the choppers. Cale gets into a fight with Stenz and ends up dropping his White House passes for himself and Emily while escaping. Having already learned of Emily from the video, Stenz, now knowing she is Cale's daughter, takes her to Walker in the Oval Office. Meanwhile, Tyler finally finishes the upload into NORAD and launches a missile at Air Force One, killing Hammond and everyone on board. Raphelson is then sworn in as acting President and reluctantly orders an air strike on the White House, which Cale is informed of.

Walker tells Cale over the White House intercom to surrender Sawyer or he will kill Emily. Sawyer ultimately surrenders himself to save Emily. However, he refuses to activate the football. When Walker threatens to kill Emily again, the alarms and sprinklers are set off by Cale setting various rooms on fire. Tyler is killed trying to escape by the bomb on the tunnel gate having been tampered with so it goes off rather than disarm when he leaves. After killing most of the remaining mercenaries and freeing the hostages, Cale is confronted by Stenz, who is ultimately killed by a grenade belt. Sawyer attacks a distracted Walker, who ultimately gains the upper hand and uses him to activate the football before supposedly shooting him dead. Using updated launch codes received by an anonymous source, Walker targets various cities in the Middle East, but before he can initiate the launch, Cale crashes into the office in a Presidential escort vehicle. Despite being pinned to the wall by the vehicle, Walker still attempts to press the launch button but Cale finally kills him with a mini-gun before he gets the chance.