Following the death of Robert F. Colesberry, director Joe Chappelle joined the production staff as a co-executive producer and continued to regularly direct episodes.

[2] David Simon had originally hoped to create a city hall spinoff show, which would run in tandem with subsequent seasons of The Wire, and had even written scripts for it.

The returning cast consisted of Dominic West as Detective Jimmy McNulty, whose insubordinate tendencies and personal problems continued to overshadow his ability;[4][5] Lance Reddick as Lieutenant Cedric Daniels, now commanding his own unit;[6][7] Kima Greggs, played by Sonja Sohn, now McNulty's new partner within the unit;[8][9] Clarke Peters as Lester Freamon;[10][11] and Deirdre Lovejoy as Assistant State's Attorney Rhonda Pearlman.

[32] Colvin commanded the Western district where the Barksdale organization operated, and nearing retirement, he came up with a radical new method of dealing with the drug problem.

[34][35] Sydnor, a rising young star in the police department in season 1, returned to the cast as part of the major crimes unit along with Pryzbylewski.

Chris Bauer (Frank Sobotka), Paul Ben-Victor (Spiros Vondas) and Amy Ryan (Beadie Russell) all left the starring cast with the third season.

[61][62] Isiah Whitlock, Jr. reprised his role as corrupt State Senator Clay Davis, who continued to be involved with Barksdale money.

[65] Omar Little's crew continued to rob the Barksdale Organization and consisted of his boyfriend Dante (Ernest Waddell), partners Tosha Mitchell (Edwina Findley) and Kimmy (Kelli R. Brown), and advisor Butchie (S. Robert Morgan).

[70] Al Brown and Jay Landsman reprised their roles as patrol division officers Stan Valchek and Dennis Mello.

The upstart Stanfield Organization introduced several new roles: Marlo Stanfield (Jamie Hector), a ruthless leader seeking to challenge Avon's dominance;[75][76] Chris Partlow (Gbenga Akinnagbe), Stanfield's chief enforcer;[77][78] Felicia "Snoop" Pearson (Felicia Pearson), Partlow's protege;[79][80] Norris Davis as rimshop owner and advisor Vinson;[65] Brandon Fobbs as crew chief Fruit;[65] and Melvin T. Russell and Justin Burley as young drug dealers Jamal and Justin.

[65] The Barksdale Organization also found several new recruits: Slim Charles (Anwan Glover), Avon's new chief enforcer;[81][82] Bernard (Melvin Jackson, Jr.), responsible for procuring disposable cell phones;[65] and Dennis "Cutty" Wise (Chad Coleman), a newly released convict uncertain of his future.

[96][97] The focus on Colvin's command of the Western District introduced several new characters both in Carver's Drug Enforcement Unit and in the Patrol Division.

Carver's squad included Kenneth Dozerman (Rick Otto),[98][99] Anthony Colicchio (Benjamin Busch), Lloyd "Truck" Garrick (Ryan Sands), and Lambert (Nakia Dillard).

-Butchie Marlo feigns retreat to let Avon move in, then has soldier Felicia "Snoop" Pearson attack Poot Carr.

Barksdale phone mule Bernard is pressed by his bored girlfriend to hurry, breaking Stringer's rule to only buy two per store.

Carver imposes a tax on Hamsterdam's dealers and buys a basketball hoop for the local kids with the money, but it is quickly destroyed.

The website's critical consensus reads, "In its third season, The Wire's taut, unflinching examination of Baltimore expands from the criminal underworld to the top of the political machine.