Brodie first appeared as a cameraman for a local news station, often intruding on crime scenes or getting in the way of investigating police in order to get the most dramatic shots possible. Upon discovering that some of his footage showed a murder suspect the homicide unit was trying to track down, he turned it over to the detectives instead of giving it to his boss for use on that night's broadcast. His decision allowed the unit to close the case, but cost him his job.
Recognizing Brodie's sacrifice, Lt. Al Giardello and Capt. Megan Russert offered him a job as videographer for the homicide unit, shooting footage of crime scenes and interviews for later use in court. He continued to film other subjects for his own amusement, eventually constructing a documentary about the unit that was revealed in the episode "The Documentary." At the end of the episode, when Giardello asked Brodie for the master copy in order to prevent any embarrassment to the detectives, Brodie revealed that he had already sold the film to PBS.
Being young, shy and prone to getting caught underfoot, Brodie found himself struggling to gain respect in the office, something that bothered him throughout his time at the station. However, he would occasionally surprise the detectives by chipping in with some observation that they had missed. At one point, he correctly deduced that Det. Frank Pembleton had stopped taking his stroke medication (which he realized because his own mother had suffered a stroke). Caught off-guard, Pembleton noted that he had underestimated Brodie. "Most people do," the cameraman replied. In Season 5, he insisted that Det. John Munch not write off a shooting death as a suicide, believing that an arrogant graduate school classmate of his had to have been involved. Munch and Sgt. Kay Howard investigated and began to share Brodie's suspicions, and he fabricated some video evidence that helped the detectives trick the classmate into exposing himself as a murderer.
Brodie left the squad between the fifth and sixth seasons; after his documentary won an Emmy, he moved to Los Angeles to develop his career. He next appeared in Homicide: The Movie, the TV movie that capped off the series, when he returned to Baltimore to visit Gee, who had been shot. His role in the film was small, and he spent most of his time off-camera, recording an operation. However, he had a pivotal scene at the very end of the film, when he informed the squad that Gee had died while in the hospital.
