Perhaps the coolest director of all time. Jo was the original Romulan director, and also helped develop the Space system with MacGyver. In 1996, when TOS Space 3.0 came online, Jo stepped down from directing the Romulans to become fulltime Space Director. He continued to develop and add things to the space system for some time. He was also very quick to help out players of all empires in developing RP plots that involved space.
Jo could be hot-tempered at times, and he did not always see eye to eye with the Klingon directorate under Izick and K'tohk. But he was extremely popular among the players at large, both because of his willingness to solicit player feedback for space innovations and because of his ability to actually deliver on what he promised in a relatively timely manner, a rarity among TOS directors.
Eventually, RL caught up with Jo, and he turned over his responsibilities as space director to Athaorh. He remained around for quite a while after that, though.
If you ever see Jo on a channel or elsewhere on TOS, be sure to greet him with a heartfelt "wug."