Marlo Stanfield is a young player in the Baltimore drug trade who gains control of the Western District and the head of his own drug outfit.
Marlo Stanfield was introduced in season 3 as an up and coming drug player controlling corners along Eastern Avenue in the West side. Marlo and his best friend Chris Partlow waged war with the Barksdale crew over this territory. His ambition was full control of the drug trade in West Baltimore.
The Barksdale organization approached Marlo through lieutenant Bodie Broadus to discuss exchanging the sharing of territory for a share of their high quality supply of drugs. Bodie had set up his own crew within Stanfield's established territory. Marlo refused to acknowledge Bodie and insisted that he move his crew away. Later Marlo had his dealer Fruit and his crew beat Bodie's team with baseball bats to prove that he wasn't going to lay down and let the Barksdale organization move into his territory. Stringer Bell visited Marlo personally to try to convince him to join the co-op; a group of Baltimore drug players who buy packages of narcotics together to receive discount and try to reduce the violence of their trade to avoid police attention. Marlo listened to Stringer without comment, and shortly after Stringer left, he warned Partlow to prepare for war.
Lieutenant Daniels' major case unit caught on to Marlo when he met with Stringer. Initially they were unsure if he was working with the Barksdale organization like many other crews in the West side. The unit went to the homicide division to learn more about Stanfield and found that he had been investigated for a murder. The police had built a case against him using a key witness who they even put under protection with a tracking device. The case disintegrated when the witness was murdered and the body found using the tracking device, which was still attached to the corpse. The investigating detective, Vernon Holley, believed that Marlo killed the witness. Holley described Marlo as "the spawn of the devil." When a failed Barksdale assault on a Stanfield corner resulted in the deaths of two Barksdale soldiers, the police realized the two gangs were at war.
The assault had been triggered by the parole of Avon Barksdale who took a more confrontational approach to the turf war than Stringer. Marlo believed that the failed assault showed a lack of strength in the Barksdale organization and discussed this with Partlow and his advisor Vinson. He organized retaliatory assaults against Barksdale territory. His soldier Snoop killed Barksdale soldier Rico in a drive-by. Avon responded by hiring a woman named Devonne to seduce Marlo and lure him to a meeting. While Marlo had sex with Devonne he did not go to their arranged meeting. Instead, he had Snoop surveil the location while Partlow waited nearby. Snoop spotted Devonne reporting to Avon, who was waiting in a parked car. Partlow drove by the car and shot and wounded Avon and killed another Barksdale soldier. Marlo and Partlow later tracked Devonne to her home and Marlo murdered her personally as she was leaving one night. The violence continued to escalate and Marlo's lieutenant LaTroy was killed.
When Stringer Bell was murdered, the police and drug gangs thought it was Marlo who had him killed. In reality, Avon had facilitated his death by giving Brother Mouzone and Omar Little information about his whereabouts. At the end of season 3, Avon was arrested for parole violation, weapons charges and drug crimes. Marlo and Chris attended his sentencing hearing. Avon acknowledges Marlo; thus conceding that the crown has been passed.
Marlo begins season 4 in control of all of the best territory in Western Baltimore. He viciously protects his realm through his enforcers, Chris (Partlow) and Snoop. When murders are committed on Marlo's behalf, they hide the bodies in vacant buildings. When Marlo's crew chief, Fruit, is killed by a dealer, Lex, from Bodie Broadus' independent crew, he is quick to order Lex' death, which is carried out by Partlow and Snoop.
Marlo furthers his reputation around the neighborhood by giving away money to children during the back-to-school period through his lieutenant, "Monk" Metcalf. He keeps his own skills and his soldiers sharp by organizing shooting practice sessions in the woods.
The major case unit targets Stanfield and begins to infiltrate his organization using wiretaps, but fail to link him to any murders because of the hidden bodies. They do manage to get Marlo on tape when he uses Monk's phone to talk to a subordinate known as "Old Face" Andre.
After Proposition Joe engineers a conflict between Marlo and Omar, Marlo agrees to join the New Day Co-Op purely to learn more about both Omar and the mounting police interest in him.
When Marlo's plan to have Omar killed in jail fails, Omar retaliates by stealing not only Marlo's package, but also the entire shipment of the New Day Co-Op. Marlo is suspicious of Proposition Joe's claim that the shipment has been stolen, and insists on some kind of satisfaction. Joe then decides to set up a meet between Marlo and Spiros Vondas in order for Marlo's fears to be allayed. Marlo is satisfied by Vondas' explanation, and begins having him followed in order to learn more about his role in importing the drugs into Baltimore.
Marlo is impressed with 14-year-old Michael Lee for standing up to him and believes that he will make a good soldier. He orders Chris and Snoop to recruit Michael into his organization. When Michael's step-father comes home from prison, Michael, after realizing no one else can help him, goes to Marlo for help and begins looking up to him once Marlo has Michael's step father killed. Marlo sets up Michael and his brother Bug in an apartment, and gives him his own corner, with Dukie, Donut, Poot, and Kenard working for him.
When Lester Freamon finally discovers Marlo's tombs in the vacant houses, a massive police investigation into the vacants begins, and the re-established Major Crimes Unit begins investigating Marlo once again.
Season 5 opens with Marlo under reduced police surveillance as the Major Crime Unit is shut down for budgetary reasons. Having been extremely cautious up until this point, Marlo and his crew relax their routine. Marlo is confident that the police have given up on him, and orders Chris and Snoop to kill a dealer named Junebug who allegedly spread rumours about Marlo being a "dicksucker". He also has them shoot up a corner of rival dealer Webster Franklin in order to force him to accept to give up his package. Snoop kills one of his soldiers during the assault.
Marlo uses Propositon Joe in order to learn more about laundering money and also about keeping money in offshore accounts. But once Marlo has no further use for Prop Joe, he has him murdered by Chris right in front of him. This allows Marlo to take over the Greek connection from Joe and to disband the New Day Co-op.
The method of communication (cellphone pictures) between Marlo and the Greeks allows the major case unit to track where and when a meet is going to take place, which allows them to catch Marlo's crew taking the very first resupply of Marlo's tenure as overall drug king. This in turn leads to the arrests of most of his crew including himself, Chris Partlow, Monk and Cheese, Prop Joe's traitorous nephew. However, because of technicalities in the way the phone taps were set up (under the guise of tapping the made-up homeless killer), Marlo and Cheese both walk free. Marlo however, cannot take anymore part in illegal activity or he will be prosecuted regardless of the technicalities. After he is released, he is first seen at an event with Levy, his lawyer, who tries to introduce him to important developers and investors. Marlo, however, is clearly uninterested and leaves after excusing himself to go the bathroom. He is then shown taking a corner with his bare hands, causing the two corner boys to run off, suggesting that he may be unable to resist the lure of the drugs game. However, after he physically forced the boys away, he realizes that his arm has been cut by a pocket knife, which is seen laying on the ground after the scuffle.
- Rico: Killed in a drive-by shooting committed by Snoop on orders from Marlo to perform a drive-by shooting on the Barksdale Organization.
- Tater: Killed in a drive-by shooting by Chris Partlow from Marlo's order to detect the supposed meeting of Marlo and Devonne.
- Unnamed Dealer: Shot to death in a vacant house by Chris Partlow on Marlo's orders
- Curtis "Lex" Anderson: Killed by Snoop and Chris on orders from Marlo for murdering the latter's lieutenant Fruit.
- Unnamed Security Guard: Killed by Snoop and Chris on orders for talking back at Marlo.
- New York Boy: Shot in a vacant house by Snoop and Chris.
- New York Drug Dealer: Shot by Chris on Marlo's orders.
- 3 New York Dealers: Killed by Snoop and Chris on Marlo's orders.
- Old Face Andre: Shot to death by Chris and Snoop on orders from Marlo as he suspected Andre that he informed the police.
- Little Kevin: Killed off-screen by Chris on order's from Marlo on suspiscions of informing the police.
- Bodie: Shot by O-Dog for suspecting of talking to the police.
- Unnamed Corner Boy: Shot by Snoop on Marlo's orders.
- Junebug and Others: Shot to death by Snoop and Chris.
- Butchie and bodyguards: Killed by Chris Partlow on Marlo's orders in an attempt to lure Omar out of hiding.
- Devonne: Shot to death by Marlo for working for the Barksdale Organization.
|Season 3 appearances|
|"Time after Time"||"All Due Respect"||"Dead Soldiers"||"Amsterdam"||"Straight and True"|
|"Homecoming"||"Back Burners"||"Moral Midgetry"||"Slapstick"||"Reformation"|
|"Middle Ground"||"Mission Accomplished"|
|Season 4 appearances|
|"Boys of Summer"||"Soft Eyes"||"Home Rooms"||"Refugees"||"Alliances"|
|"Margin of Error"||"Unto Others"||"Corner Boys"||"Know Your Place"||"Misgivings"|
|"A New Day"||"That's Got His Own"||"Final Grades"|
|Season 5 appearances|
|"More with Less"||"Unconfirmed Reports"||"Not for Attribution"||"Transitions"||"React Quotes"|
|"The Dickensian Aspect"||"Took"||"Clarifications"||"Late Editions"||"–30–"|