Frog is a white street-level dealer whose allegiances are never made clear. He is seen early in season two distributing a package for Ziggy Sobotka (and stealing from him in the process), and later negotiates with Nick Sobotka to distribute another. During the early stages of season two's investigation, he sells heroin to Thomas "Herc" Hauk and is photographed by Kima Greggs and Ellis Carver.
White Mike is a mid-level East side drug dealer with his own territory. He supplied Ziggy Sobotka with packages of narcotics to distribute but their relationship soured when Ziggy failed to make adequate profit from the package. McArdle was supplied by The Greek's smuggling operation and was arrested as part of an investigation into that operation. He was quick to turn against his suppliers and gave up all the information he had.
Brook Yeaton is also an on set dresser for the show.
Avon Barksdale hired him to protect the weakened Barksdale operation from Proposition Joe's dealers, who were working the Barksdale towers as part of a secret agreement between Stringer Bell and Proposition Joe. Mouzone brought a team of soldiers in and promptly shot the dealers' leader "Cheese" with a rat shot (plastic pellets). He then informed Cheese that the next bullet in the chamber was a copper jacketed hollow point bullet. Proposition Joe's dealers were so intimidated that all he had to do to keep them away was sit on a nearby bench reading magazines. To maintain his alliance with Proposition Joe, Stringer duped Omar Little into believing that Mouzone was responsible for the brutal murder of Omar's boyfriend Brandon. After Omar confronted Mouzone and shot him, he realized that he was tricked and called the ambulance for Brother Mouzone himself. Mouzone informed Stringer that their agreement was "absolved", and returned to New York.
In season three, Mouzone returned to Baltimore to search for Omar. He located Omar's boyfriend Dante with advice from Baltimore local Vinson. Mouzone beat Dante until he revealed Omar's whereabouts. After he tracked Omar down he suggested that they team up to kill Stringer Bell. Avon gave Mouzone a time and a place to find Stringer, because Mouzone threatened his connection to New York and hence his supply of drugs if he did not. Omar and Mouzone planned an ambush and killed Stringer together. Before returning to New York, Mouzone released Dante and gave Omar his weapon to dispose of.
The Deacon is a West Side church figure who is involved in many community projects. He also has many contacts within the city’s academic population. He is a friend of teacher Grace Sampson and helps her ex-boyfriend Dennis "Cutty" Wise when he is released after a long prison sentence. Initially he tries to encourage Cutty to enroll in a GED program, but Cutty is not interested in this idea. The deacon then helps Cutty to open a community boxing gym. He puts Cutty in touch with State Delegate Odell Watkins through the politically influential Reverend Frank Reid to help with obtaining the necessary permits for the gym. He also helps Cutty to get a paying job working as a school custodian at Edward Tilghman Middle, where Grace teaches the eighth grade.
The Deacon is also friends with Howard "Bunny" Colvin. When Colvin was Western District police commander the Deacon often served as his conscience. Colvin started three drug tolerant zones in his district and the deacon was dismayed at the poor conditions addicts faced in these areas and convinced Colvin to involve public health academics in providing services for the addicts now he had gathered them into an easy to reach area. Colvin was forced to retire because of his actions and the deacon found him a new job working with a sociologist in studying the prevention of repeat violent offender behavior.
In his youth Melvin Williams, the actor who plays the Deacon, was a real-life drug kingpin who was arrested by series writer Ed Burns in 1984 when he was a Baltimore city police officer. Creator David Simon was responsible for covering the arrest for The Baltimore Sun at the time. Williams received a 34-year sentence for his crimes and much of the evidence against him came from a wiretap investigation like the one featured in the first season of the show.
She is played by Genevieve Hudson-Price, the daughter of author Richard Price, who writes for the show.
Brother Mouzone recovered and returned to Baltimore for revenge. He had Lamar seek out Omar in various gay bars having learned that he was homosexual. Lamar resented the task and his visceral homophobia made him confrontational with those he came across while searching for Omar. Eventually Lamar was approached by Omar’s boyfriend Dante allowing Mouzone to capture him and find Omar.
DeAndre McCullough, the actor who plays Lamar, was the basis of an eponymous character in David Simon's The Corner.
Squeak is the girlfriend of Bernard, a mule in the Barksdale organization. Bernard was responsible for supplying the organization with disposable mobile phones and was told to buy no more than two phones at any one outlet and provide receipts for his purchases. Squeak's nagging convinced Bernard to start breaking these rules.
Squeak was an old associate of Bubbles and their association allowed the police to use her as an inroad to the Barksdale organization. Bubbles put Squeak and Bernard in touch with Lester Freamon who was a posing as a conman who could provide them with phones at lower price. With Squeak's encouragement, Bernard accepted Freamon's offer and began buying solely from him on the condition that he provide him with receipts. Freamon gave Bernard pre-wiretapped phones that eventually brought down the Barksdale organization. When the investigation was closed with the arrest of Avon Barksdale Bernard and Squeak were also brought in. Bernard joked that he could not wait to go to jail to get away from Squeak.
Sherrod continues to deal drugs and is involved in an assault on Namond Brice when they vie for territory. He also becomes a drug addict. Eventually, he returns to Bubbles, saying he wants to get away but he owes Jojo money. Bubbles offers Sherrod the chance to return home and says he will help with the debt. Bubbles, however, had previously prepared a lethal "hot shot" of narcotics he intended to use to kill another addict who had repeatedly harassed and traumatized Bubbles. Sherrod finds the vial Bubbles has prepared and takes it himself, dying soon afterwards.
Walon is an HIV-positive recovering drug addict. He first appears in season one when Bubbles and Johnny see him speaking at a Narcotics Anonymous meeting. They see Walon again in the projects trying to get his nephew to give up drugs. Bubbles' conversations with Walon help him realise that he wants to get clean. When he makes a serious attempt, Walon gives him advice on keeping clean, which Bubbles is unable to stick with. Years later, when Bubbles is locked in a medical rehab facility, Walon visits him to again help him with his sobriety and grief. In later episodes, it is revealed that Walon has become Bubbles' sponsor.
Walon is played by singer/songwriter and recovering heroin addict Steve Earle. Earle also performs the theme song for Season 5.
While in the hospital for that beating, Johnny discovers he is HIV positive. In the season three finale he dies from an overdose and his partially rat-eaten body is discovered in a vacant house in the "Hamsterdam" free zone that Major Colvin had set up.
Johnny is based on a young white homeless addict that David Simon met while researching The Corner. This man would follow Simon's subject, drug addict Gary McCullough, around.