He made his debut in Season 6, but departed in Season 10. He has not been reintroduced in the CGI reboot to date. This makes him one of the least serving human characters from the Original Series in the show as he was only in the show for 5 years.
Colin McFarlane voiced J.J. in both dubs. In the UK dub, he spoke with a London accent. In the US dub, he spoke with an Orlando Florida American accent.