Henry Walker was the United States Secretary of War for the Noah Grace administration.
Not much is known of Walker's past, except that he previously hailed from Chicago, Illinois. He was sixty-three years old (as of 1951), and a retired colonel who had become Secretary of War at some point in time under the Grace Administration. However, Walker undeniably disliked Noah Grace for his controlling personality and rule over the United States; and likewise did not care for the other members of Grace's cabinet (only with the exception of Vice-President Harvey McCullen, whom he was considered his only friend and ally) for their sycophantic loyalty to Grace, and they in turn apparently did not like him either. Although, Walker was accepted into their inner circle as he has powerful connections to the military, in which Grace was highly depended upon during the height of the Chimeran War. When Chimeran forces had focused their attention on North America, Walker had everything in his power of bringing the U.S. military onto a wartime footing.
On November 16th, 1951 President Grace revealed to his cabinet of Project Omega, a possible contingency plan of a exclusive negotiation between America and the Chimera, in which both Walker and Vice-President McCullen were highly disagreed to this compromise. Walker decided to secretly record the project, using a pocket-sized wire recorder to collect evidence against Grace and the other cabinet members who agreed with the idea, whom Walker obviously considered as traitors. During another meeting, when the President reveals the conditions of the truce, which involved in having only the United States spared at the expense of the rest of the world, Walker snapped and protested in outrage. After the meeting, Walker and his wife Myra defected and left Washington, D.C. and headed for Chimera-controlled Chicago, where they would meet the city's resistance group, Freedom First, and get their recordings of Grace and Project Omega broadcast on public radio.
Just after leaving Washington, the Walkers' absence was immediately acknowledged by the Grace Administration in which President Grace ordered the capture of the Walkers, either dead or alive. Chief of Staff William Dentweiler was assigned to find the Walkers.
On November 29th, 1951, the Walkers were being driven by a man named Twitch Saunders, a runner who drove people and supplies into Chimeran-controlled territory. They then discovered that they were being followed, and the Walkers bailed out into a ditch and Twitch performed a U-turn in an attempt to escape. The Walkers climbed out of the ditch just in time to see Twitch's car explode. The pair were then captured by the Chimera and a prisoner guide named Norma Collins. They were put into a flatbed truck driven by a Hybrid along with other human prisoners. Later the truck crashed and they were forced to walk, and stayed in an old hotel kitchen for the night. During that night, one of the prisoners was killed by the Chimera (presumably for food). The next day the prisoners were then joined by another two group of prisoners before being led into a large open pit mine, belonging to Hasbro Mining, near Madison, Wisconsin. At the pit supplies were dumped every so often, which led to groups competing for control of the supplies. Walker was part of the "Fair and Square Squad", which divided the resources evenly. During one drop, Walker hit a man named Marcus Tolly, who had assaulted Walker. Walker was then told and warned by his friend Harley Burl to stay out of sight as Tolly was seen talking to Collins, who was the person who chose prisoner(s) every three days for conversion, and suggested that he planned to get Collins to take Walker away. The next day Walker's wife Myra was taken out of the pit, into what was revealed as a conversion center filled with Spinners. A few days later Walker killed Tolly by lighting him on fire using gasoline and a Zippo lighter, in what Walker knew was revenge on the man he believed was responsible for his wife's death. When a breakout using a escape tunnel was attempted, Walker was the 131st person to go, as positions were chosen by lottery; however, the breakout was discovered before he could escape.
When a SRPA rescue mission, led by Nathan Hale, was conducted on the mining pit with directions from Harley Burl, who escaped from the pit, arrived a few days later, it was discovered that Walker had been brought into the conversion center before the attack arrived. They were able to find him in one of the cocoons and located Walker's recorder in the corpse's back. Hale would later listen to the recordings during the VTOL ride back to base. After hearing the recorder's information, Hale would then go on to kill Grace during his negotiation with Daedalus.