After his parents died when he was only young, Bobby was taken care of by his elder sister Eileen, who also had a daughter, Caitlin. Family life was made more difficult after Eileen's husband Jimmy was killed in a spat with a fellow dockworker. To help his sister out, Bobby often went on stick-up jobs with his friend Sonny, who was sleeping with Eileen behind his back.
In 1934, Bobby accidentally shot Vito Corleone whilst trying to protect him from an Irish gang member Stevie Dwyer. Even though Sonny knew Bobby accidentally shot his father he still chose to kill his childhood friend Corcoran.
Personality and traits
Garrulous and warm-hearted, Bobby exhibited all the positive traits of a stereotypical Irishman. He was also fiercely loyal to his family, and it was only after insulting his sister Eileen that Sonny Corleone was able to provoke Bobby into attacking him. Sonny used this as justification for killing him.