Surprised nobody’s mentioned Vic Mackey yet.
And Carl Kolchak if you’re as old as me.
Steve McGarrett, Dan Williams, Chin Ho Kelly, etc. (original “Hawaii Five-O”)
Jonathan and Jennifer Hart, and Max (“Hart to Hart”)
Doctors Marcus Welby and Steven Kiley (“Marcus Welby, M.D.”)
There are others, but those are a few of my favorites.
Some other classic icons: Archie Bunker, Lou Grant, Professor Charles Kingsfield, and Thomas Magnum.
President Bartlett
And Jim Rockford
Both are excellent nominees. I would also include Shane Vendrell (and by extension, Boyd Crowder).
Does anybody else remember another Darren McGavin character: Captain Grey Holden?
If I were to consider The Shield’s supporting cast, I liked Dutch and Aceveda.
Vic Mackey
Dr. Perry Cox
George Constanza
Denny Crane
Alan Shore
Chuck Bartowski
John Casey
Alex P. Keaton
Barney Stinson
Buffy Summers
Both those actors have had significant roles in Sons of Anarchy, along with Detective Curtis Lemansky
Homer Simpson
Kenny McCormick
The Tick (NOT the Patrick Warburton one)
There is a lot of love for Rockfish on this board. 
Cheyenne Bodie and Paladin for me.
Amen! Do you have any strong feelings about any of the other WB Westerns of that era?
– Bronco
– Sugarfoot
– The Lawman
Also, did it strike you as odd that Cheyenne was always getting beat up by some much smaller bad guy?
Cosmo Kramer
Barnabus Collins
I would so totally watch this show!
Gandy, is that you?
Lenny Briscoe
Louie DePalma
I’ve got to ditto Bret Maverick.
Ooh, and your mention of Napoleon Solo reminds me of
Ilya Kuryakin! and thus I add
Donald “Ducky” Mallard to my lists.
I was alive and remember the theme songs to the other shows, but was too young to appreciate or remember Cheyenne Bodie or Peter Gunn, though I still the theme music for the latter.
I could only watch what my parents watched, so I never saw any of those shows in primetime, but I did catch a season or two of Lawman on Encore last year. I enjoyed it, but for me, nothing beats Cheyenne. When I was a kid, he was better than Superman.
They run him on Encore, too, and I see a lot more in the episodes than I did when I was a kid. Some of the episodes were blatant plagiarisms of movies, like “To Have and Have Not,” and “Treasure of the Sierra Madre.” IMO they did a great job of getting the essence of those great movies in a 45-minute episode.
I honestly don’t remember Cheyenne getting beat up by smaller guys, unless it was a gang of them. Of course, almost everybody was smaller than he was, so I guess he couldn’t win them all.
I should add:
Leroy Jethro Gibbs
Michael Westen
President David Palmer
Artemus Gordon
Capt. Malcom Reynolds
Richard Castle
(man crush? No, why do you ask?)
President Bartlett
Dept Marshall Raylon Givins
Boyd Crowder
Great choices. I’d like to add Bart Maverick. Jack Kelly was a better actor at this point in his career than James Garner was at the time he played Bret.
Sue Ann Nivens played by Betty White. A joy to watch.
Candy played by April Bowlby on Two and A Half Men. A complete joy to watch. A complete modern mastery of the Gracie Allen type character.