Bernie Kessoff was a Hollywood movie producer in 1960 of the alternate timeline where an elderly Biff Tannen used the DeLorean time machine and the Grays Sports Almanac to make his younger self a millionaire.
Bernie met Biff at a celebrity party, and used Biff's admiration of celebrities to convince him to start a movie studio.
Bernie managed Tannen Pictures while Biff partied with celebrities. However, Kessoff wasted millions of dollars on himself, and didn't spend much on the film he promised Biff that Tannen Pictures would produce. When Biff finally started being concerned about the studio's finances, Bernie put in a last ditch effort to get the film made.
That film, Dreams of a Madman, starred Rock Hudson, Judy Garland, Harpo Marx, and Boris Karloff. It premiered on November 6, 1960 to scathing reviews. When Biff discovered that Tannen Pictures was being repossessed, Biff sent Bernie to bet on a horse race. Unbeknownst to Bernie, the horse track was controlled by the crime boss Deke Dirkin, who had Bernie killed when he mentioned that Biff had sent him.
After urinating on Bernie Kessoff's star on the Hollywood Walk of Fame, Biff left Hollywood and went back to his hometown of Hill Valley.
When Marty McFly and Dr. Emmett Brown changed history by intercepting the Gray's Sports Almanac prior to its use in 1955, this resulted in Tannen Pictures never coming into existence at all. As a result, it could be surmised that since Biff Tannen remained in Hill Valley, he never met Bernie Kessoff and therefore his murder never took place.
Bernie was a sleazy leech of a man, as well as an extremely incompetent producer and filmmaker.
- Back to the Future (IDW Publishing)