I believe I know who is the longest serving member, still alive and active. He also is the oldest one too I think:
Sonny Franzese - Made in late 1930's and is either 99 or 97 years old.
I will assume Sonny got made in 1938, which would give him 78 years of service.

Also know that Harry the hunchback served for almost 73 years but he is dead.

I find this topic interesting because I fully understand how a young kid could become enticed and brainwashed by the allure of it all but, cannot understand how these older guys do not see the writing on the wall about their own mortality. Maybe, just maybe, if they accept the fact that they were wrong for so long and, ask God for forgiveness, their may be life after death for them.

Even the vicious gangster Tony Spilotro, chose to ask for forgiveness at the hour of his death by asking his killers if they would let him say a prayer before they kill him.

So, besides those 2, what others can I add to the list?
Even interested if Furio knows of anyone from his country who can fit this category.