In the comics, John Grayson and his wife were performers in Haley's Circus with their son, Dick Grayson, while preparing for a performance, Dick overhears Anthony "Boss" Zucco, a well-known and feared crime-lord, threaten the performers unless the circus' owner pays extortion money. The owner refuses, and that night young Grayson watches in horror as his parents' high wire snaps, sending them hurtling to their deaths, all while many of Gotham's elite watched on. Dick felt responsible, because he hadn't warned his parents in time.
In other media
In Batman Forever, Dick's dad appears along with his wife and son Mitchell (created for the film) but is not named. They are The Flying Graysons and try to stop Two-Face from blowing up the Circus. He dies along with his wife and Mitchell, leaving Dick on his own.