The Lone Wolf TV series

It starred Louis Hayward as Michael Lanyard, whose private detective work took him all over the world. One of the interesting things is that he was always helping out "old friends." Given that Hayward was about 45 years old at the time the series was made, it is difficult to believe that his character had had time enough in his far-flung life to make all that many "old friends." He is, of course, supremely smooth and suave at all times.