Robert Blake carried-over Baretta's signature unlit-cigarette-in-the-mouth from his vice cop character in "Busting" (with Elliott Gould) the previous year, 1974.
Andrew Prine, as Baretta's cop friend, Andy, seemed as if he would be a regular. They had good chemistry, and even had nicknames for each other as if having worked together for years: Andy called Baretta "Midget" and Baretta called Andy "Stringbean" but Andy never returned. Actor Andrew Prine would, however, come back for another episode in Season 3, but as another character.
Tom Ewell's Billy owns a pool hall, and Baretta has to come to him. In the episodes and seasons that follow, Billy would simply go to Baretta's apartment or he'd already be the lobby, becoming a sort of sidekick on the show.
The character "Rooster" (this show's Huggy Bear) is played as gay, flamboyant, with both Robert Blake and Andrew Prine not only teasing him, but doing a cliche gay imitation to goad him. In future episodes and seasons, Rooster becomes simply a pimp-like snitch that Baretta uses for info.
Very similar plot to Robert Blake's cop film the year before, Busting, where he, like Baretta, holds an unlit cigarette in his mouth, and follows around a mob kingpin, playing with his head, needling him.