George Callen Senior was the Grandfather of G. Callen and Amy Calllen. His daughter was Clara Callen. He was an OSS Agent and CIA Agent who killed five members of the Comescu Crime Family. He was eventually tracked down and killed by the Comescu's.
After his death his daughter Clara ran with her son and daughter to the US and lived in Los Angeles for while. He parachuted into Romania in 1944 to help king Micheal overthrow the fascists. After the war he hunted war criminals of the Comescu Family which started the feud until G. Callen ended the feud.
His name "supposedly" gives G. Callen his name to be George Callen Junior.