Grand Theft Auto III/Liberty City Stories
In Grand Theft Auto III, Lazlow is the host of talk radio station Chatterbox FM. He states that he got this job after being fired from the rock station, presumably V-Rock. During the events of GTA: Liberty City Stories (circa 1998), Lazlow was the host of Chatterbox, but the show itself shared airtime with several other radio shows on LCFR (Liberty City Free Radio), including the Electron Zone and Coq 'O' Vin. Lazlow states his dislike for sharing airtime, and mentions that he and Donald Love are in talks of making Chatterbox a 24/7 show/station.
Grand Theft Auto Vice City/Vice City Stories
As mentioned above, Lazlow was the DJ of V-Rock, a Vice City radio station. During this time, he was often antagonized by callers about his integrity as a rocker.
In GTA: Vice City Stories, which takes place two years prior to the events in GTA: Vice City, Lazlow is an intern for Couzin Ed, the then DJ of V-Rock. Ed would constantly pick on Lazlow for being an "effeminate dork" to put it lightly. Ed also made an appearance in the original Vice City game as a caller, ranting about how Lazlow took his job away from him.
Grand Theft Auto San Andreas
Lazlow was the host of WCTR's Entertaining America radio show in San Andreas. He usurped Billy Dexter, the show's original host. Lazlow hosted interviews with OG Loc and Chris Formage (the head of The Epsilon Tract, a cult of his own design). During his interview with Chris, Darius Fontaine called in and argued with Chris about his methods for "saving" people, and claims that his Inversion Therapy program is the way people should help themselves.
Grand Theft Auto IV
In Grand Theft Auto IV, Lazlow hosted a roving reporter-esque show known as Integrity 2.0, where he would travel around Liberty City, interviewing random pedestrians. This "version" of Lazlow shows a somewhat more egotistical side of him. This is presumably to show that he is now "being real", which happens to mean he is really a drug-addled, sex-crazed star of sorts.
Grand Theft Auto V
In Grand Theft Auto V, Lazlow is the co-host of Chattersphere, a talk radio show on WCTR. He is also the host of a TV talent competition show called Fame or Shame. GTA V is the first time Lazlow has made an actual in-game appearance, rather than just hearing his voice on the radio.