The renowned physicist behind the formula E=mc² is Albert Einstein. This equation, which expresses the equivalence of energy and mass, is a cornerstone of modern physics and fundamentally changed our understanding of the universe. Einstein developed his theory of relativity in the early 20th century, revolutionizing concepts related to space, time, and gravity. His groundbreaking work laid the foundation for numerous advancements in physics and technology, making him one of the most influential scientists in history.