Mr. X

I always thought "Mr. X" was okay...
Sorta cool, but no big deal.
But someone played him in a recent TV release and that piqued my interest enough to go to imdb.com and learn some things about him. I was surprised, and have changed my mind about him.
Can you guess who he is?

-When he learned Bela Lugosi had died penniless, he quietly paid Lugosi's funeral expenses.
-Lee J. Cobb credits him with literally saving his life.
-After a traumatic incident in a telephone booth, he forever-after carried a roll of dimes in his pocket.
-He was only 5' 7" tall.

A flawed, but basically nice man.