Simon Riley had a very traumatic childhood while growing up in Manchester, England because of his heartless father. On most days, his father brought dangerous animals back and taunted him with them, even going so far to force him to kiss a snake or threaten to kill him with them. When he and his younger brother Tommy got older, Tommy would always wear a skull-mask at night to scare Simon. Simon's father would sometimes take him to the Bone Lickers concerts. At one concert, his father made him laugh at the death of a prostitute who was addicted to drugs.
Joining the Military
Simon used to be an apprentice butcher at a grocery when he grew up. After the September 11 attacks occurred, he joined the military. He was an expert soldier which got him into the Special Air Service.
Return from the Military
Simon came back home one day on January 2003 and found his family in a predicament. His mother was constantly getting cheated on and his brother was addicted to drugs. He opted not to go back to his life at the military until he fixed their lives. In March 2004 Riley beat his father for abusing him and his mother and threw him out of the house. He then helped Tommy get rid of his drug addiction and made him marry a woman named Beth in June 2006. Riley was seen as the best man at Tommy's wedding. Beth also gave birth to a young boy named Joseph who would become Riley's nephew.
Going after Manuel Roba
Simon was pulled out from shipping out for an operation in Iran and was set to take the Zaragoza Drug Cartel down that was headed by Manuel Roba. When he and his team made their move on the Day of the Dead, the commanding officer, Major Vernon, betrayed them to the enemy by getting the three of them captured and brought to a torture and brainwashing facility. There, he was driven mad and tortured. At one point, he was buried alive and left by his captors. He used this opportunity to escape and got back home.
It took him four months to recover from all of that, but he was still having temper-management issues, and as a result he was not accepted back into the military. After having an episode with his former-colleague, Kevin Sparks, his entire family was killed by Sparks and Marcus Washington.
He killed Sparks and Washington and went after Roba once more. He ambushed Roba's right-hand man, Gilberto and tortured Roba's location out of him. He arrived at Roba's compound and stole all of the information on the company and killed Roba. Riley fought Roba's guards and burned his mansion and compound. When he left, he was approached by General Shepherd and recruited into Task Force 141 under the name of Ghost.
Task Force 141
At one point, he was sent alone against terrorists in a grade school in Ukraine. He deliberately got himself caught and told the terrorists and the children about his past before the rest of his team arrived to free him and the children. One girl asked him if the story of Simon "Ghost" Riley was true and if Riley was Ghost. He responded saying "true enough to that lot".
On October 8, 2013, a joint Task Force 141/Delta Force operation codenamed Operation Kingfish was launched. Ghost worked alongside John Price, John "Soap" MacTavish, Gary "Roach" Sanderson, Sandman and Derek "Frost" Westbrook as they hunted down Vladimir Makarov. They assaulted the main compound and are able to recover some intel, but got ambushed by a bomb, forcing the team to evacuate. During the evac, Soap was wounded by an RPG and was partially knocked out. An AC-130 tried to defend the team as they sprinted toward their evac point, but was shot down, leaving the team completely vulnerable. Price selflessly stayed behind to facilitate the team's escape and was wounded and captured.
Following Makarov's massacre at Zakhaev International Airport, Ghost assisted in the operation in Rio de Janeiro to locate and capture Alejandro Rojas, the man who supplied Makarov with weapons and ammunition, maintaining radio contact with Captain MacTavish and Roach while they searched for Rojas's assistant. After MacTavish and Roach began pursuing the assistant, Ghost met up with them at the Hotel Rio and joined the chase. Once the assistant was taken down by Roach, Ghost prepared to interrogate him through torture. Ghost was heard via radio for the rest of the mission as he attempted to pursue Rojas through the favela. After the capture of Rojas, Ghost was heard requesting extraction from Command, but to no avail. Despite this, Ghost managed to narrowly escape the favela with Captain MacTavish and Roach aboard Nikolai's helicopter.
Infiltration of the Russian Oil Rig / Rescuing Prisoner 627
After escaping South America, Ghost joined the rest of Task Force 141 as they prepared a counterattack with the US 6th Fleet against the Russians. Using information recovered from Rojas, they learn that Prisoner 627, the only man Makarov hated worse than the Americans, was locked away in a gulag, though the path leading to the prison was blocked by oil rigs, which were captured by the Russians and turned into makeshift SAM sites. Targeting the least-defended rig, Ghost and the rest of the 141 and Navy SEALs infiltrated and cleared the rig of hostiles and rescued several hostages in order to safely deactivate the SAM sites. Following the mission, Ghost joined the attack on the gulag holding Prisoner 627, where he would take control of gulag's security systems and guide his allies to the prisoner, who was soon revealed to be Captain John Price.
With Captain Price back in their ranks, he soon devised a contingency plan to end the war in America by infiltrating a Russian submarine base. Though Ghost and his team were initially separated from Price and Roach following their insertion, they would later meet up and converge on the Russian base, where Price took control of a Russian sub. However, Ghost was shocked when Price launched an ICBM at Washington D.C. where the Russian-American war raged on. Ghost contacted Command about Code Black, which was the statement that a threat of a nuclear weapon was launched and must be disposed of immediately. It was possible that he retracted this though after he learned about Price's intention.
The Search for Vladimir Makarov and Death
Using resources from his blank check, Shepherd deduced the last two safe havens for Makarov and his men at a safehouse on the Georgian-Russian Border and an airplane boneyard in Afghanistan. Knowing they have to be at two different places at once, Ghost nominates himself and Roach, along with a bulk of Task Force 141, to take the safehouse, while Soap and Price investigate the boneyard. After raiding the safehouse however, Makarov was nowhere to be found, though the safehouse was loaded ("A bloody gold mine" as Ghost said) with intel. Ghost, along with Roach, Ozone and Scarecrow, with sniper support from Archer and Toad, protected a DSM from Makarov's men while it downloaded sensible information regarding Makarov's operations. After finishing the download, the team headed to the LZ that was set up by Shepherd, though Ozone and Scarecrow were both gunned down by enemy mortars, and Roach was injured. Ghost managed to get Roach to the LZ, but both were ultimately betrayed by Shepherd, who fatally shot the two in the chest at point-blank range with a .44 Magnum, just before Ghost could use his ACR. After Shepherd retrieved the DSM from Roach, Ghost's body was thrown into a ditch and set on fire along with Roach's.