Charles Hood is an agent with British Intelligence.
Take a former champion amateur boxer, throw in a runner with near Olympic speed, a marksman who actually competed in the Pentathlon a decade earlier, and a competitor in the two-man bobsled World Competitions. Throw in a cosmopolitan air, clothes from only the best tailors and boot-makers, and exquisite tastes in wine, art, and, of course, women. Naturally, he is quite well off, negating the need to work a normal job. Have him work anyways but with the cover of buying for even richer people rare paintings and sculptors.
Hood is ruggedly handsome with dark brown hair with a slight curl to it and dark grey eyes. He stands just over six feet tall weighing 177 lbs and is in excellent physical shape even though he is probably in his early 40s at the start of the series.
To cap it all, have him travel the world buying and selling priceless pieces of art, all while doing the odd clandestine work for both the British Secret Service and the Foreign Office. That is Charles Hood, spy extraordinaire. Did I mention he is noted in Who's Who, noted for being a sportsman and art connoisseur?
What isn't mentioned there, though, is the fact that, even as he does work for MI-6, he is also the key agent for a group called the Circle, comprised of the richest men in Europe and dedicated to keeping the peace. War brought uncertainty and danger, bad for business. Peace opened markets and allowed profits to be made without the risk of losing it all. To help keep the peace, the Circle worked behind the scenes. When action was called for, Hood came in.