A football star and all-around nice guy, Johnny grew up idolizing his father, Jack Sterling, who moonlighted as Steel Sterling. As Steel Sterling, Jack had been a private detective, superhero, movie star, and bodybuilder, before settling into a role as mayor, loving husband, and caring father. Although Johnny turned out as athletic as his father, the soft-spoken teen enjoyed delving into advanced science studies (much to the chagrin of his football coach). Although intimidating in stature, Johnny shared his father's calm good-natured demeanor, quick to put people at ease.
When the Brain Emperor attacked a reunion of the original Mighty Crusaders, Johnny's parents were apparently killed, but he was saved by his parents' old teammate The Shield, as were the five other teenagers that had been at the party. From this old hero Greg learned the truth about his parents, and learned they had wanted him to follow in his father's footsteps should anything ever happen to them. Hesitant at first, Johnny embraced his destiny as a hero after watching a video letter his father had made in case the worst should happen. After receiving a treatment meant to replicate the accident that gave the his father superpowers, Johnny became the new Steel Sterling, and joined the New Crusaders.