The fourth season of the television series The Wire commenced airing in the United States on September 10, 2006, concluded on December 10, 2006, and contained 13 episodes.

[3] David Mills, Emmy-award winner, Homicide and The Corner writer and college friend of Simon, joined the writing staff in the fourth season.

[2] The focus of the fourth season shifted between a local school, the mayoral election, police department politics and action on the street corners.

The returning starring cast consisted of Dominic West as Officer Jimmy McNulty, the formerly insubordinate detective who attempts to shed his ability and his problems in favor of a better life.

[9] Robert Wisdom reprised his role as former western district commander Howard "Bunny" Colvin,[10] who has become a field researcher after a short stint working in hotel security following his retirement from the Baltimore Police Department.

[22][23] Jim True-Frost portrayed Roland "Prez" Pryzbylewski,[24] a former member of the Major Crimes Unit who has become a teacher in an inner city school after inadvertently killing a fellow officer in season three.

Both Wood Harris (Avon Barksdale)[38][39] and Idris Elba (Stringer Bell)[40][41] left the starring cast in the final episode of the third season.

Proposition Joe (Robert F. Chew), the East Side's cautious drug kingpin, became more cooperative with the Stanfield Organization following the death of Stringer Bell.

[52][53] Tray Chaney continues to portray former Barksdale crew chief Poot Carr, who joins the Stanfield organization this season.

[58][59] Isiah Whitlock, Jr. reprised his role as corrupt State Senator Clay Davis whose involvement with Barksdale money causes him trouble with the Major Crimes Unit.

[60][61] Omar Little's crew shifted focus to the Stanfield Organization and the New Day Co-op and consisted of his new boyfriend Renaldo (Ramón Rodríguez), partner Kimmy (Kelli R. Brown), and advisor Butchie (S. Robert Morgan).

[76][77] In the western district, Carver's squad includes Anthony Colicchio (Benjamin Busch), Lloyd "Truck" Garrick (Ryan Sands), and Lambert (Nakia Dillard).

The shift of focus to the schools saw the introduction of four young actors in major recurring roles this season: Jermaine Crawford as Duquan "Dukie" Weems;[86] Maestro Harrell as Randy Wagstaff;[87] Julito McCullum as Namond Brice;[88] and Tristan Wilds as Michael Lee.

[90][91][92][93] Other new characters from the school included Tootsie Duvall as Assistant Principal Marcia Donnelly;[94] David Parenti (Dan DeLuca), a Professor of Social Work at the University of Maryland who works with Bunny Colvin in the school to study potential violent offenders;[95] Stacie Davis portrayed Miss Duquette, a doctoral student who works with Parenti and Colvin; Aaron "Bug" Manigault (Keenon Brice), Michael Lee's younger brother; Kenard (Thuliso Dingwall), one of the younger members of Namond Brice's circle of friends;[96] and Richard Hidlebird as Principal Claudell Withers.

[97] "...a dazzling three-ring circus of interwoven plot threads, and its take on America’s drug war makes Miami Vice look like a Saturday-morning cartoon..." The fourth season of The Wire is listed as one of the highest rated individual TV seasons of all time on Metacritic with a score of 98 out of 100 based on 21 critics—including 17 perfect score reviews.

The website's critical consensus reads, "Realistically flawed characters in harrowing, uncompromising circumstances, along with engrossing storytelling, make The Wire one of TV's top dramas of its time.

-Bubbles Epigraph: "If animal trapped call 410-844-6286" -Baltimore, traditional Bubbles turns himself in and attempts suicide but is rescued by Landsman, who sends him to rehab.

Carcetti uses the bodies to distract from the budget on advice from chief of staff Michael Steintorf, insisting to a disappointed Wilson that he can solve both problems as governor.