Moltisanti was born in New Jersey to an alcoholic mother named Joanne. During his youth Chris's father Dickie had problems with alcohol and spent most of Chris's childhood in prison before he was killed shortly following his release. Moltisanti also often played on a farm with his cousins Tony Soprano and Tony Blundetto who bullied him relentlessly.
Soprano came to regard Chris with affection and felt responsible to look out for him due to Tony's close relationship with Dickie. He mentored him to become part of the dimeo crime family and fondly considered him a nephew. Chris assisted Tony in beating up debtor Alex Mahaffey. Moltisanti made his bones by killing Emil Kolar due to a dispute the family was having over garbage routes.
He complained to his uncle that he wasn't made for this and felt he didn't get enough credit for his resolution of the problem. Chris caused further problems for Tony when he and his friend Brendan Filone highjacked trucks, which were under the protection of Tony's Uncle Junior. They were made to pay restitution but Brendan decided to pull off another heist and accidentally killed the driver. For this Junior had right-hand Mikey Palmice murder Brendan, though Chris only got a mock execution. Chris wanted to kill Mikey to avenge Brendan but Tony forbade him and resolved the conflict by making Junior a "lightning rod" for the FBI to bear the brunt of the investigations while allowing him to control the organization.
During Tony's later war with Junior Moltisanti and Paulie Gualtieri were able to kill Mikey, thus avenging Brendan's death. Christopher was put in charge of a scam for the family.
His underlings Matthew Bevilaqua and Sean Gismonte tried killing him in a foolish attempt to gain favor with Richie Aprile, Chris survived and killed Gismonte but was hospitalized. Soprano was enraged by the attack on his nephew and personally took Bevilaqua's life. Shortly after this Chris recovered and was called to dismember Richie Aprile's body.
Tony used his influence to have Chris made however this caused his friendship with Paulie Gualtieri to sour as an envious Paulie bullied him for by subjecting him to random wire searches and sniffing the panties of his girlfriend Adrianna. After Chris complained to his uncle Paulie was reprimanded by Tony. Paulie then confronted Chris and warned him against involving Tony in their conflicts again.
Chris and Paulie were sent by Tony to collect money from Valery, a Russian mobster in debt to Silvio Dante. Paulie needlessly provoked the situation and instigated a fight with Valery, who escaped into a woods which ultimately resulted in Paulie and Chris being stranded there. While on the phone to Tony, Paulie attempted to blame the disaster on Chris which he overheard. This led to a confrontation where Chris pointed his gun at Paulie. When the men were rescued by Tony and Bobby Baccalieri Paulie lied that Valery caused the fight and Chris decided to cover for his friend.
Moltisanti was present When Jackie Aprile Jr. (son to a close friend of Tony) robbed a mob card game. He expressed a desire to see the boy killed. After Tony said no Chris accused him of only following the rules when it was convenient and said he no longer loved him. Soprano then grabbed his nephew and demanded to be given respect.
Though Tony saw to it that Aprile was dealt with Motlisanti's questioning of him led to a rift in the relationship. Tony Made Chris his main contact in criminal dealings to insulate himself from prosecution. He took Chris to a house of Detective Barry Haydu Who Tony claimed was Dickie's killer then had Chris kill him. Soprano mainly did this to reconcile the relationship and ensure the loyalty of his nephew.
Motlisanti's drug use spiraled out of control and viciously beat Adrianna. Tony was advised by Junior to kill Moltisanti but instead he organized an intervention, which ended with Paulie and Silvio laying a beating on Chris. After this Chris graduated rehab and was entrusted by Tony with organizing the hit on Lupertazzi Boss Carmine Lupertazzi.
When Tony decided to back out of the plan Moltisanti assigned Benny Fazio and Petey La Rossa to murder the hired help.
After hearing rumors that Adrianna had performed oral sex on Tony he wrongly assumed them to be true (though this had more to do with Tony's lack of opportunity than anything), he beat Adrianna and kicked her out of the house. He pulled a gun on Tony who prepared to kill him but Blundetto Stepped in and saved his life.
Later Blundetto and Soprano ribbed on Chris over his addictions. When Tony made him split the difference of a cigarette smuggling operation with Paulie Chris complained that he had a wedding to pay for prompting Tony's sarcastic suggestion that he should cut out the open bar. Adrianna told Chris she was an FBI informant.
He revealed this information to Tony, who then had her Killed. When he wept out of grief Tony showed little sympathy and assaulted his nephew. Blundetto almost started a war with New York by killing Phil Leonardo's brother Billy.
Tony feared Phil would target Blundetto's family and sent Chris into hiding. After seeing Phil threaten his mother Joanne, he moved his location. Following Soprano's killing of Blundetto, Moltisanti was tasked with burying the body.
After the two men were involved in a car accident brought on by Chris's drug addictions Tony reasoned that he would always be a liability and impulsively killed his nephew. He feigned grief to his family but admitted in therapy that he was tremendously relived to be rid of someone he felt he could no longer trust.