John Kessler was the head of the military operations for the Organization who burned Michael Westen . He works for Anson Fullerton after he betrayed the Intelligence of the United States he worked for many past years.
Little information is known about the past of John Kessler. He worked in the past for an Intelligence based in the United States. He sells top-secret information to some terrorists, so he was captured and placed in a federal prison. Anson Fullerton meets him secretly and gives him a job in his Organization. John Kessler accepts immediately and escapes the prison with the help of mercenaries who worked for Anson Fullerton.
Anson Fullerton gives the command to lead the operations around the world for him. John Kessler accept to lead the burn agents and the mercenaries who work for the Organization . With Management , he represents the face of The Organization , so he can cover the true leader Anson Fullerton . He lives in Venezuela during the active years of the Organization. He leads the operations in his safe house in Venezuela.
The death of Carla Baxter is the beginning of the end for the Organization . He sends Vaughn to convince Michael to accept to work with the Organization but he refuses. With the list of the agents who work for Kessler, Michael and the CIA capture one by one the mercenaries, agents and contacts who are members of the Organization.
During the beginning of the fifth season, John Kessler is alone with his bodyguards in his safe house. All the PMCs and agents who work for him are captured or killed. When he was attacked by the CIA and Michael, he escapes to his safehouse and unlocked the door to his private room. Michael blows the room with a grenade but Kessler is lying facedown, dead. Michael assumed that the grenade killed him, but Kessler appears to have committed suicide to avoid interrogation, so he can protect the mysterious leader of the Organization.
Anson Fullerton reveals later he engages an assassin to execute Kessler so he can't be captured and interrogated by the CIA.