Peter Merkel was a small-time thief in Keystone City, who had a "triple-jointed skeleton", i.e. he was born with the ability to bend his body almost any way he wanted. As the Rag Doll, he fought the original Flash repeatedly during the 1940s. In modern years, the Rag Doll returned as a member of the Secret Society of Super-Villains. Feeling his age, he eventually quit his costumed career, instead making use of his talents as an orator. Seeking his followers among the petty criminals, the homeless and the young, he founded his own "Rag Doll Cult" that was responsible for a particularly brutal and violent crime wave in Opal City. After a clash with members of the Justice Society, Merkel was believed dead, but had actually survived, his body damaged beyond repair.
Most recently, his youth and health were returned to him through a deal with the demon Neron. After briefly joining Culp’s army of villains during the Opal City riots, the Rag Doll peacefully walked away from the fight. His last words mentioned returning to Keystone City and his old "friend", Jay "Flash" Garrick. He did indeed return, but was relatively inactive and instead chose to set up a new cult in Lake City. From here, he was approached by members of the Injustice Society to help them retrieve the Cosmic Key from JSA headquarters. He joined them, but soon betrayed them, trying to seize the Key for himself – this was what they had expected him to do, and he died in the act, killed as Johnny Sorrow returned to Earth. He is survived by an estranged son, who sometimes operates as Ragdoll III.