During World War II, he was the architect of the CIA's MK/Ultrahuman research program. Ludmilla Serebrennikov supplied him with samples of warlock hoping to convince him to let her into the United States of America. He discovered the drug's ability to transfer consciousness and traded bodies with a young GI.
Claiming to be his own long lost son Henry Harrigan Jr afterward, he founded and became the head of IDEA. As he got older, he developed cancer and started looking for a new body. He decided to use Creed McIlveen. Before the transfer completed, Vincent Wheaton contacted the intelligence in the warlock. It incinerated Harrigan's body, gaining enough energy to finally escape from Earth. (PROSE: Warlock)