As children, Johnny and James were best friends. However, their lives were changed when the Chimera emerged from Russia, and their father rejoined the Royal Air Force. Johnny and his brother wanted to join their father and entered the RAF alongside him. Johnny and James became pilot and gunner respectively. When their father was later killed in combat, James began to have doubts about military service and left the RAF which he subsequently fell in with his friends, who had become robbers and vandals. As a result, Johnny had to try and look after James and their mother whilst trying to serve his country.
One evening Johnny finally had enough of James' mischief. They had an argument and Johnny told James that he had to stop committing crimes with his friends after having heard from his friend Pete that the army was planning to put the cities on lockdown and crackdown on crime. He banned James from going out into the cities where his friends had robbed and vandalized. James angrily retorted that Johnny never really care about his family, but always cared more about appearing like a hero. Johnny realized that James did not really know how badly the war was happening in Europe and that humanity was on the brink of losing the entire continent. After their argument, James left home and joined a street gang due to his belief that Johnny was trying to control him.
War in Europe
A few days later Johnny was called to aid France, and his mother was put in the care of the Royal Air Force. When the war advanced to France, Johnny and his RAF squadron fought the Chimera and became a decorated war hero. He and his squadron flew 38 missions over Germany and Belgium. During this time, Johnny became friends with his gunner Ryan.
Johnny and his squadron later volunteered for a high-risk mission over Berlin. Unfortunately, during the battle, his plane was shot down by a Chimeran fighter. Johnny and Ryan survived, but they were presumed dead by the British military. They were stuck 150 miles behind Chimeran lines, and slowly began to make their way back to the front, dodging Chimeran patrols and living off of what little food they could find.
After a week of moving back towards France, they encountered a group of mostly-German refugees who were unknowingly moving into Chimeran territory. Johnny and Ryan joined them into helping them escape west into France, and becoming their de-facto leaders. However, as they brought the refugees back towards France, one refugee disobeyed an order from Johnny and set a fire during the night, attracting a Chimeran patrol. The disobedient refugee was killed, as was Ryan. Johnny was able fight off the patrol. Feeling guilty over the deaths of Ryan and the refugee, he brought the refugees back to France. They were brought to the relative safety of Dunkerque, where they were to be evacuated, although Johnny stayed behind to help the Maquis in attempting to destroy the tunnels the Chimera were digging under the English Channel. The mission was a failure: the Chimera were able to dig under the English Channel and break into London. Subsequently, Johnny returned to England to battle the Chimera. On the flight to London he briefly met Rachel Parker.
When Johnny returned to England, he once again volunteered for a high-risk mission - this time over Chimera-occupied London. Before going, he saw James one last time. James was in a hospital, after being wounded while saving his squad from a Titan. Johnny told James that while doing this he disobeyed a direct order and that he read his bootcamp record and come to the conclusion that James was as self-centered and irresponsible as ever. He encouraged James to shape up and stop being rebellious. The conversation degenerated into an argument and Johnny left.
Shortly afterward, Johnny went on his mission over London. During the flight, Stalkers shot down his plane. Johnny survived the crash, but was captured and taken to a conversion center in Manchester, where he was infected with the Chimeran virus. On May 15th, 1951, he was 'saved' by his brother and a squad of soldiers, but when they learned that he was infected, James gave Johnny a mercy killing. Shortly afterward Johnny's body was put to rest and his brother adopted his flight jacket. Subsequently, James had an emotional breakdown and developed a personal vendetta against the Chimera. James' anger over his brother's infection led him to abandoning his unit and destroying twenty-six conversion centers across Britain in the process. James would later don his brother's flight jacket as a reminder to his brother's death and would later come to terms with his vendetta.
- Both Graysons, Johnny and James held the same rank of Lieutenant, but the former held the RAF equivalent, Pilot Officer. while James had it in the Navy.
- In Resistance: Retribution Johnny Grayson is referred to solely as Jonny and in the comics as Johnny.