Dragnet debuted inauspiciously. The first several months were bumpy, as Webb and company worked out the program's format and eventually became comfortable with their characters. Friday was originally portrayed as more brash and forceful than his later usually relaxed demeanor. Gradually, Friday's deadpanned, fast-talking persona emerged, described by John Dunning as "a cop's cop: tough, but not hard; conservative, but caring". Friday's first partner was Sergeant Ben Romero, portrayed by Barton Yarborough, a long time radio actor.
When Dragnet hit its stride, it became one of radio's top rated shows. Webb insisted on realism in every aspect of the show. The dialogue was clipped, understated, and sparse -- influenced by the hard-boiled school of crime fiction. Scripts were fast moving, but didn't seem rushed. Every aspect of police work was chronicled, step-by-step. From patrols and paperwork, to crime scene investigation, lab work and questioning witnesses or suspects. Webb was a stickler for accurate details, and Dragnet used many authentic touches, such as LAPD's actual radio call sign, KMA-367, and the names of many real department officials, such as Ray Pinker and Lee Jones of the Crime Lab, or Chief of Detectives, Thad Brown.
Two announcers were used. Episodes began with announcer George Fennemen intoning the series opening:
"The story you are about to hear is true. Only the names have been changed to protect the innocent."
Hal Gibney described the basic premise of the episode. For example, "Big Saint", from April 26th, 1951, begins with:
"You're a detective sergeant. You're assigned to auto theft detail. A well organized ring of car thieves begins operations in your city. It's one of the most puzzling cases you've ever encountered. Your job -- break it."
The story usually began with footsteps and a door closing, followed by Joe Friday intoning something like:
"Tuesday, February 12th. It was cold in Los Angeles. We were working the day watch out of Robbery Division. My partner's Ben Romero. The boss is Ed Backstrom, Chief of Detectives. My name's Friday."
Friday offered voice-over narration throughout the episodes, noting the time, date, and place of every scene as he and his partners went through their day investigating the crime. The events related in a given episode might occur in a few hours or might span a few months. At least one episode unfolded in real time, in "City Hall Bombing", from July 21st, 1949. Friday and Romero had less than 30 minutes to stop a man who was threatening to destroy the City Hall with a bomb.
At the end of an episode, announcer Hal Gibney would relate the fate of the suspect. They were usually convicted of a crime, and sent to the state penitentiary or a state mental hospital. Murderers were often executed in the manner proscribed by law. Occasionally, police pursued the wrong suspect, and criminals sometimes avoided justice, or escaped, at least on the radio version of Dragnet.