smooth operator

A smooth operator is someone who handles situations or people with effortless charm and skill, often to advance their own interests.

The term carries undertones of manipulation—a smooth operator knows exactly what to say and when to say it, making them persuasive but potentially untrustworthy.

He's a smooth operator who somehow always gets what he wants.

The phrase was popularized by Sade's 1984 hit song of the same name.