Lazlow Jones is the character that has appeared the most number of times in the GTA series.
Technically, some fans might argue that radio DJs shouldn't count. However, Lazlow Jones still shows up in-person in GTA 5 and GTA Online, so he is a real character within the universe.
As a result, it's only fair to include his involvement as a DJ in the previous games. He speaks a ton in the games he shows up in, too, so it's not like he's barely in the titles he's present in.
Most other characters tend to only show up in one game. A few are lucky to show up in two. Lazlow Jones has appeared in an astonishing nine titles so far. No character is close to that feat, and that's not even mentioning how Lazlow Jones is likely to show up in future titles.
It's doubtful any character will be usurping the real-life DJ anytime soon.
Which character has made the most appearances in the GTA series?
As already mentioned, it's Lazlow Jones. He is a real-life celebrity who has helped Rockstar Games several times as a DJ for their radio stations.
Surprisingly, his role extends past mere voice acting. He has also helped write and produce several in-game scripts, often in a witty and creative manner. As far as appearances go, he has appeared in nine games.
Which games has Lazlow Jones appeared in?
Physically, Lazlow Jones can be seen in GTA 5 and GTA Online. In the former, he is a host for "Fame or Shame," an in-universe reality TV show parodying several similar talent shows (predictably, he does not get along with the GTA 5 protagonists).
In the latter, he shows up in the Nightclub property when the GTA Online protagonist tries to meet Tony Prince and can later be found lounging around.
He has also appeared in seven other GTA titles as a DJ host of various radio stations. Canonly, his first appearance is in GTA Vice City Stories as an intern working for Cousin Ed in V-Rock.
By the time GTA Vice City starts, he's the head DJ of V-Rock and is more relaxed than his GTA 5 counterpart. It wasn't all sunshine and rainbows for the young DJ, as he would later be fired for either asking for a higher wage or for having sex with a female intern, depending on which story the player believes.
Later on, everybody's favorite DJ would show up in GTA San Andreas, GTA Liberty City Stories, GTA 3, and eventually, GTA 4 and its DLC episodes (with both counting as one appearance, given not much is different between the two "appearances").
In GTA San Andreas, he hosts WCTR and clearly showcases how out-of-touch he is compared to more modern media personas.
In GTA Liberty City Stories, Lazlow Jones is the host of LCFR, later renamed to Chatterbox FM in GTA 3. Finally, he shows up in GTA 4 as the host of Integrity 2.0 (after once again losing his previous gig for one reason or another).
Here, he was more violent and ruthless. By the time the GTA 4 DLC episodes happen, one of his sponsors (ZiT) abandons him. Aside from that, he mostly remains the same between these episodes and GTA 4.
Games that Lazlow Jones has not appeared in
There is no knowledge of any future games that he may or may not appear in, so those games will not factor in this discussion. Instead, past games are more relevant for today's topic of discussion.
He obviously does not appear in GTA 1 or GTA 2, as those games were very limited in how radio stations worked. Likewise, he does not appear in GTA Advance or GTA Chinatown Wars.
Unfortunately, the former doesn't have radio stations and instead plays loops of a few songs (hence no need for Lazlow Jones). Chinatown Wars does have radio stations (five in the DS and 11 in the PSP version), but the DJs are more limited in what they do in these games compared to the other HD universe GTA titles.