- "You were all handpicked 'cause you're the best at what you do. Inter-unit rivalry has no place here. Berets, Delta, SEALs, Force Recon, I don't give a shit. This is who we are now. This is Operation Cerberus... and you are my dogs of war. The enemy operates without regard to honor or rules. So neither will we. Our mission is simple. We capture, interrogate and execute high-value targets."
- ― Ray Schoonover to the Cerberus Squad[src]
Operation Cerberus was a covert military operation aimed at eliminating targets stationed in Afghanistan. Given its illegal nature, it had to fund itself, which it did by smuggling heroin into the United States in the corpses of dead soldiers.
During the War in Afghanistan and after the fall of the Taliban government, multiple terrorist organizations would emerge to challenge the coalition-led government in Kabul, leading to the longest war in American history.
William Rawlins, determined to decisively end the conflict, teamed up with Major Ray Schoonover to create an operation that would accomplish his goal. The operation would be carried out by Cerberus Squad, a team of elite US soldiers, and would be centered in Kandahar. Their missions would involve capturing, interrogating, and killing high-value targets.
Unbeknownst to the squad, these missions were not only illegal but were unsanctioned by United States Congress or the CIA, who Rawlins claimed were fine with it. The interrogations were led by Rawlins who used torture to extract information and often involved the execution of the captive once the info was obtained.
Since Operation was illegal and did not have congressional approval, Rawlins decided to use heroin trafficking to finance the operation. With the help of Morty Bennett, Rawlins smuggled large amounts of heroin from Afghanistan to the United States, using the bodies of US soldiers. These drugs would then be sold on the streets by Schoonover, who became a powerful drug lord known as the "Blacksmith" in the process.
A member of the Afghan National Police Ahmad Zubair began investigating the movement of heroin traffic and murders in Kandahar. He discovered that the illegal activities were being carried out by the United States Armed Forces soldiers, and relayed his suspicions to Dinah Madani, a Homeland Security Liaison. She assured him that he would be protected for his testimony.
Unfortunately, Zubair was captured by Cerberus Squad before he could testify. He was falsely labeled as a terrorist by William Rawlins, who tortured him to try to find out who else knew about his illegal operation. When Zubair did not reveal his confidant, Rawlins ordered Frank Castle to execute Zubair and bury his body outside of Kandahar.
As Operation Cerberus progressed, terrorist groups caught onto Cerberus Squad's tactics. They leaked information that a high ranking terrorist leader was located in Kandahar in an isolated compound. William Rawlins ordered Cerberus Squad to attack the compound despite the risk of ambush and a terrain unsuited for helicopter evacuation. The battle proved to be a disaster, with Major Ray Schoonover losing an arm and most of the squad dead or injured. The remaining squad members were saved due to the actions of Frank Castle, who single-handedly fought his way into the compound and killed the insurgents inside.
When returning to base, Rawlins coldly and repeatedly asked the surviving squad members if they eliminated their target, unconcerned with the large casualty rate. Frank Castle proceeded to punch Rawlins in the side of head hard enough to puncture the orbital socket and blind him in the left eye. With the squad heavily injured and the loss of confidence in Rawlins' leadership, Operation Cerberus shut down soon after. 
- "You think this all of this is about a bad drug deal? That's what you see. You're losing your touch, Frank. Your kids, at the park? Nah. Who cares? That's never what this has been about. It's about what happened with you. With all of us. Kandahar. You think they would ever let that go?"
- ― Ray Schoonover to Frank Castle[src]
Unbeknownst to anyone of the Cerberus Squad, Gunner Henderson secretly recorded the execution of Ahmad Zubair and sent it to NSA analyst David Lieberman. Lieberman revealed it, sending the footage to Dinah Madani and other illegal operations to the public, gaining the attention of the New York Bulletin. Rawlins returned to the United States and joined forces with Billy Russo who funded Anvil to work as a security force under Russo. Ray Schoonover was promoted to the rank of Colonel and began to plotted to take over the drug empire within New York City, eventually rivaling against Madame Gao's own heroin trade.
Castle was blamed for the tape's release by Schoonover and Rawlins, who decided to have him and his family killed in Central Park by tipping off three gang groups. Though Russo was ordered to have them killed, he refused but didn't stop the event from happening. Castle survived the massacre and went on a manhunt for anyone who was involved in his family's murder.
- In the comics, Ray Schoonover smuggled drugs out of Vietnam in order to finance anti-communist forces until he was discovered and forced to commit suicide by Frank Castle.
- Billy Russo compared Operation Cerberus with the Phoenix Program.