William James Sidis had a genius level IQ but spent his final days in poverty and isolation

William James Sidis could read The New York Times before he turned two. By six, he spoke several languages. And at just nine years old, he was accepted into Harvard University. But instead of fame or fortune, Sidis wanted something much simpler — peace and privacy. Despite being called “the smartest person who ever lived,” he spent his final years alone, broke and forgotten.

A Genius From the Start

William James Sidis was born on April 1, 1898, in Boston, Massachusetts. His parents, Boris and Sarah Sidis, were Ukrainian immigrants and both highly educated.

Boris was a well-known psychologist and Sarah was a doctor. From the beginning they poured their time and resources into their son’s education, filling his world with books, maps and lessons.

Their investment paid off quickly. At 18 months old, Sidis could already read The New York Times. By age six, he was fluent in English, French, German, Russian, Hebrew, Turkish and Armenian.

He even created his own language as a child though no one knows if he used it later in life. Along with his studies, he wrote poetry, a novel and even drafted a constitution for a utopian society.

Harvard’s Youngest Student

When Sidis was nine, Harvard accepted him but he wasn’t allowed to attend classes until he turned 11. Still, his reputation as a child prodigy had already spread.

In 1910, while still a student, he gave a lecture to the Harvard Mathematical Club about the fourth dimension, a concept so advanced that most people in the audience couldn’t understand it. Those who did called it brilliant.

He graduated in 1914 at just 16 years old. Reporters swarmed him for interviews, curious about his plans but instead of chasing fame, Sidis said, “I want to live the perfect life. The only way to live the perfect life is to live it in seclusion. I have always hated crowds.”

The Question of His IQ

Over the years, experts have debated just how intelligent William James Sidis really was. His official IQ test results were lost, so historians have had to estimate.

Average IQ is around 100. Albert Einstein’s has been estimated at 160, Leonardo da Vinci’s at 180 and Isaac Newton’s at 190. Sidis’s IQ, according to those estimates, was somewhere between 250 and 300, possibly the highest ever recorded.

But Sidis himself saw no glory in numbers. His brilliance only made it harder for him to connect with others. Despite his genius, he struggled to find happiness in a world that didn’t understand him.

Trying to Live a Normal Life

After Harvard, Sidis briefly taught mathematics at Rice Institute in Houston, Texas. But being younger than many of his students made life difficult and he eventually left the job.

In 1919, he was arrested during a Boston May Day Socialist March and sentenced to 18 months in prison for rioting and assaulting an officer — crimes he didn’t commit. The incident pushed him further into isolation.

Afterward, he took on a series of low-level office jobs, like bookkeeping and accounting, just to survive.

Whenever people discovered who he really was, he quit and moved on. “The very sight of a mathematical formula makes me physically ill,” he once said. “All I want to do is run an adding machine, but they won’t let me alone.”

The Last Years of the “Smartest Man Alive”

In 1937, The New Yorker published a story mocking Sidis, portraying him as a failed genius. Furious, he sued the magazine for invasion of privacy and libel. The judge dismissed the case, ruling that once someone becomes a public figure they remain one forever. It became a landmark case in privacy law but for Sidis, it was one more humiliation.

After losing his appeal, Sidis disappeared from the public eye again. He lived quietly, working small jobs and avoiding attention. On July 17, 1944, he died of a cerebral hemorrhage in his Boston apartment. He was only 46 years old.

When his landlady found him, he had no money and few possessions. The man once hailed as “the smartest person in the world” had died alone, living the simple and private life he had always wanted.