He occasionally has disagreements with higher-ranking officers but for the most part performs well, and has thereby gained a reputation as both a reliable commander and an above-average investigator within the force, in stark contrast to some of his superiors and peers, most of whom display varying degrees of corruption and unreliability.

Daniels was the lieutenant of the Baltimore Police Department's Narcotics Unit, and the shift commander for detectives Kima Greggs, Ellis Carver, and Thomas "Herc" Hauk.

Daniels meets with Deputy Commissioner Ervin Burrell, who tells him the case should be made with buy busts in a fast, straightforward investigation.

There, he meets State Senator Clay Davis' driver Damian "Day-Day" Price, later discovered to be a bag man involved with the Barksdales.

However, rather than seize the Barksdale money in Day-Day's possession, Daniels is forced to return the funds with no further investigation, to avoid raising Davis' ire.

Daniels contemplates quitting to become a lawyer, but reconsiders when Valchek insists that he be given command of a special detail to investigate stevedore union leader Frank Sobotka.

Russell blossoms into a capable investigator with Daniels's team and is instrumental in coming up with the idea of cloning the port's computers to monitor smuggling.

Sobotka's son Ziggy is arrested for killing the Greek's fence, George "Double G" Glekas, and his nephew Nick is proven to be involved in drug dealing.

To protect his family, Daniels's team convince Sobotka to act as an informant on the Greek and arranged for him to return with a lawyer the next day.

[1] Burrell follows through with his promise and lets Daniels form a permanent Major Case Unit, consisting of McNulty, Greggs, Freamon, Prez, Sydnor, and a new recruit, Caroline Massey.

Daniels gets commended several times by several senior figures throughout the BPD due to his good police work, including Burrell, Rawls, and Major Howard "Bunny" Colvin, amongst others.

Greggs meets with Daniels to discuss a transfer after Rawls appoints the abrasive Lieutenant Charles Marimow to head the MCU.

Mayor-elect Tommy Carcetti observes the meeting and is impressed that Daniels prioritizes quality felony arrests over statistical reductions in crime.

Daniels is invited to lunch with Carcetti and takes his offer to be appointed commander of the Criminal Investigations Division (CID) under Rawls.

Burrell and Davis convince city council president Nerese Campbell to oppose Daniels, hinting that they plan to revisit the previous corruption allegations against him.

As CID colonel, Daniels clears Herc of a racial profiling incident and assists Freamon in building a case against Marlo Stanfield.

Freamon discovers evidence of dead bodies in vacant row houses and asks Daniels for more manpower for a citywide search.

Daniels is outraged when Carcetti closes the MCU due to budgetary problems, leaving the investigations into Davis, Stanfield, and the vacant murders unresolved.

He and Pearlman arrange a meeting with Carcetti and State's Attorney Rupert Bond, leading to the mayor approving a two-man detail for the Davis case.

However, the story runs with a quote, invented by reporter Scott Templeton, falsely implicating Daniels in causing Burrell's departure.

[8] Daniels is promoted to commissioner after the homeless killings and the vacant murders are solved, but resigns from the position over threats from Campbell and his refusal to "juke the stats".

In the final flash-forward montage, Daniels is shown practicing as a criminal defense lawyer before Pearlman, who recuses herself as a newly commissioned judge.