Dean Travers from Three's Company. He was a shady man, but a funny man.

My favorite supporting TV show character by far is Cat Grant from Lois and Clark: The New Adventures of Superman. It's a shame she was only on the series for one season. For such a small part, though, Tracy Scoggins really managed to make the character very memorable. I was actually fortunate enough to tell her just how cool I thought she was in person when I met her at a convention several years ago. To this day, it's still one of my fondest convention memories of all time.

Bob Vance, Vance Refrigeration. 

Waldo Geraldo Faldo from Family Matters.

A couple of my other favorite supporting characters, Barney Fife from The Andy Griffith Show and Fonzie from Happy Days, were so popular with fans that they even outshone the main characters of their respective shows. In Fonzie's case, he pretty much eventually became the star of Happy Days.

Andy had mentioned he and Barney were cousins early in the series, but they never said anything about being cousins later on.

Mr Magic wrote :

Andy had mentioned he and Barney were cousins early in the series, but they never said anything about being cousins later on. -end quote