The term first entered the popular lexicon following the release of the film "Cadillac Man". In the film, the character of Larry (played by Tim Robbins) is holding a group of people hostage. He releases some of the hostages, but instructs them to tell the police that "I'm a no-shit guy." The hostages then run from the building one by one, screaming "He's a no-shit guy!"
"Whatever you promised Mike, you'd better deliver. He's a no-shit guy."