no more Mr. Nice Guy

Meanings

1. expressing that an implied individual has ceased being pleasant, and will now resort to unpleasant means to attain their objectives.

Etymology

The phrase was originated by Walter Winchell in 1960. He wrote a syndicated show-business column in newspapers entitled On-Broadway, wherein he told a joke about Adolf Hitler using the phrase when the Soviets invaded Berlin in 1945. The phrase was later popularized in the Alice Cooper song of the same name.