The economist known for the theory of the invisible hand is Adam Smith, often referred to as the father of modern economics. He introduced this concept in his seminal work, "The Wealth of Nations," published in 1776. The invisible hand metaphor describes how individuals pursuing their self-interest can unintentionally benefit society as a whole through market activities, leading to resource allocation and economic efficiency. Smith's ideas laid the groundwork for classical economics and have influenced economic thought and policy for centuries.