The Chief (Edward Platt) is the head of CONTROL. Although sarcastic and grouchy, the Chief is intelligent, serious, and sensible. He began his career at CONTROL as "Agent Q". (He joined the organization back when they assigned letters rather than numbers.) He is supportive of Agents 86 and 99 and rates them as his two closest friends, but he is frustrated with Smart for his frequent failures and foul-ups. As revealed in the season-one episode "The Day Smart Turned Chicken", his first name is Thaddeus, but it is rarely used. His cover identity (used primarily with 99's mom) is "Harold Clark". Another time, when KAOS arranges for the Chief to be recalled to active duty in the U.S. Navy (as a common seaman with Smart as his commanding officer), his official name is John Doe.
The interesting part of that Wikipedia synopsis for me is that the Chief was recalled to active duty in the US Navy. As such, I think we have a candidate for another appearance by the Chief in the main TV Universe.
THE CASE OF THE SLANDERED SUBMARINER
From the IMDb:
Perry moves to military court to defend a submariner of two murders - one his wife. The second victim is an officer investigating the murder and in charge of approving a new device for the Navy from a company bought by his father-in-law.
I’m not saying this has to be considered as official. Your mileage may vary. But it works for me.