On a chilly February afternoon in 1953, a gangly American and a fast-talking Brit walked into the Eagle pub in Cambridge, England, and announced to the assembled imbibers that they had discovered the “secret of life.”

Even by the grandiose standards of bar talk, it was a provocative statement. Except, it was also pretty close to the truth. That morning, James Watson, the American whiz kid who had not yet turned 25, and his British colleague, Francis Crick, had finally worked out the structure of DNA.

Everything that followed, unlocking the human genome, learning to edit and move genetic information to cure disease and create new forms of life, the revolution in criminal justice with DNA fingerprinting, and many other things besides, grew out of the discovery of the double-helix shape of DNA.

It took Watson decades to feel worthy of a breakthrough some consider the equal of Einstein’s famous E=MC₂ formula. But he got there. “Did Francis and I deserve the double helix?” Watson asked rhetorically, 40 years later. “Yeah, we did.”

James Dewey Watson, Nobel Prize winner and “semi-professional loose cannon” whose racist views made him a scientific pariah late in life, died Thursday in hospice care in New York after a brief illness, according to officials at his former laboratory, Cold Spring Harbor Laboratory. He was 97.

Born April 6, 1928, in Chicago, he was the son of a bill collector for a mail-order school who had written a small book about birds in northern Illinois. The younger Watson originally hoped to follow his father’s passion and become an ornithologist. “My greatest ambition had been to find out why birds migrate,” he once said. “It would have been a lost career. They still don’t know.”

At 12, the brainy boy who read the World Almanac for pleasure appeared on the popular radio show “Quiz Kids.” As is often the case for the gifted, his teen years were trying. “I never even tried to be an adolescent,” Watson said. “I never went to teenage parties. I didn’t fit in. I didn’t want to fit in. I basically passed from being a child to an adult.”

He was admitted to the University of Chicago at 15, under a program designed to give bright youngsters a head start in life. It was there he learned the Socratic method of inquiry by oral combat that would underlie both his remarkable achievements and the harsh judgments that would precipitate his fall from grace.

Reading Erwin Schrodinger’s book, “What Is Life?” in his sophomore year set the aspiring ornithologist on a new course. Schrodinger suggested that a substance he called an “aperiodic crystal,” which might be a molecule, was the substance that passed on hereditary information. Watson was inspired by the idea that if such a molecule existed, he might be able to find it.

“Goodbye bird migration,” he said, “and on to the gene.”

Coincidentally, Oswald Avery had only the year before shown that a relatively simple compound — deoxyribonucleic acid, DNA — must play a role in transferring genetic information. He injected DNA from one type of bacterium into another, then watched as the two became the same.

Most scientists didn’t believe the results. DNA, which is coiled up in every cell in the body, was nothing special, just sugars, phosphates and bases. They couldn’t believe this simple compound could be responsible for the myriad characteristics that make up an animal, much less a human being.

Watson, meanwhile, had graduated and moved on to Indiana University, where he joined a cluster of scientists known as the “phage group,” whose research with viruses infecting bacteria helped launch the field of molecular biology. He often said he came “along at the right time” to solve the DNA problem, but there was more to it. “The major credit I think Jim and I deserve is for selecting the right problem and sticking to it,” Crick said many years later. “It’s true that by blundering about we stumbled on gold, but the fact remains that we were looking for gold.”

The search began inauspiciously enough, when Watson arrived at the Cavendish Laboratory at Cambridge University in late 1951, supposedly to study proteins. Crick was 12 years older, working on his PhD. When they met, the two found an instant camaraderie. “I’m sure Francis and I talked about guessing the structure of DNA within the first half-hour of our meeting,” Watson recalled.

Their working method was mostly just conversation, but conversation conducted at a breakneck pace, and at high volume. So high, they were exiled to an office in a shabby shack called the Hut, where their debates would not disturb others.

In January 1953, the brilliant American chemist Linus Pauling stole a march on them when he announced he had the answer: DNA was a triple helix, with the bases sticking out, like charms on a bracelet.

Watson and Crick were devastated, until they realized Pauling’s scheme would not work. After seeing an X-ray image of DNA taken by crystallographer Rosalind Franklin, they built a 6-foot-tall metal model of a double helix, shaped like a spiral staircase, with the rungs made of the bases adenine and thymine, guanine and cytosine. When they finished, it was immediately apparent how DNA copies itself, by unzipping down the middle, allowing each chain to find a new partner. In Watson’s words, the final product was “too pretty” not to be true.

It was true, and in 1962, Watson, Crick and another researcher, Maurice Wilkins, were awarded the Nobel Prize in physiology or medicine. Franklin, whose expert X-ray images solidified Watson’s conviction that DNA was a double helix, had died four years earlier of ovarian cancer. Had she lived, it’s unclear what would have happened, since Nobel rules allow only three people to share a single prize.

In the coming years, Watson’s attitude toward Franklin became a matter of controversy, which he did little to soothe by his unchivalrous treatment of her in his 1968 book, “The Double Helix.” “By choice, she did not emphasize her feminine qualities,” he wrote, adding that she was secretive and quarrelsome.

To his admirers, this was just “Honest Jim,” as some referred to him, being himself, a refreshing antidote to the increasingly politically correct world of science and society. But as the years passed, more controversies erupted around his “truth-telling” — he said he would not hire an overweight person because they were not ambitious, and that exposure to the sun in equatorial regions increases sexual urges — culminating with remarks in 2007 that he could not escape. He said he was “inherently gloomy” about Africa’s prospects because policies in the West were based on assumptions that the intelligence of Black people is the same as Europeans, when “all the testing says, not really.”

He apologized “unreservedly,” but was still forced to retire as chancellor of Cold Spring Harbor Laboratory, the Long Island, N.Y., institution he had rescued from the brink of insolvency decades earlier. Afterward, he complained about being reduced to a “non-person,” but rekindled public outrage seven years later by insisting in a documentary that his views had not changed. This time, citing his “unsubstantiated and reckless personal opinions,” the laboratory rescinded the honorary titles it had bestowed, chancellor emeritus and honorary trustee.

Mark Mannucci, director of the documentary “American Masters: Decoding Watson,” compared him to King Lear, a man “at the height of his powers and, through his own character flaws, was brought down.” Those sympathetic to Watson said the problem was he didn’t know any of his Black colleagues. If he had, they argued, he would have immediately renounced his prejudices.

Following his DNA triumph, Watson spent two years at Caltech before joining the faculty at Harvard University. During this period, he worked to understand the role ribonucleic acid (RNA) plays in the synthesis of proteins that make bodily structures. If the double-stranded DNA contains the body’s master plan, the single-stranded RNA is the messenger, telling the cell’s protein factories how to build the three-dimensional shapes that make the whole. Watson’s 1965 textbook, “Molecular Biology of the Gene,” became a foundation stone of modern biology.

As great as was his obsession with DNA, Watson’s pursuit of, and failure to obtain, female companionship was a matter of only marginally less critical mass. At Harvard, he recruited Radcliffe coeds to work in his lab, reasoning that “if you have pretty girls in the lab, you don’t have to go out.” He started attending Radcliffe parties known as jolly-ups. “Here comes this 35-year-old and he wants to come to jolly-ups,” said a biographer, Victor McElheny. “He was constantly swinging and missing.”

His batting average improved when he met Elizabeth Vickery Lewis, a 19-year-old Radcliffe sophomore working in the Harvard lab. He married her in 1968, realizing by only days his goal of marrying before 40. On his honeymoon, he sent a postcard back to Harvard: “She’s 19; she’s beautiful; and she’s all mine.” The couple had two sons, Rufus, who developed schizophrenia in his teens, and Duncan.

The same year, Watson finished writing “The Double Helix.” When he showed it to Crick and Wilkins, both objected to the way he characterized them and persuaded Harvard not to publish it. Watson soon found another publisher.

It was certainly true his book could be unkind and gossipy, but that was why the public, which likely had trouble sorting out the details of crystallography and hydrogen bonds, loved it. “The Double Helix” became an international bestseller that remained in stock for many years. Eventually, Watson and Crick made up and by the time the Englishman died in 2004, they were again the boon pals they’d been 50 years earlier.

After their discovery of DNA’s structure, the two men took divergent paths. Crick hoped to find the biological roots of consciousness, while Watson devoted himself to discovering a cure for cancer.

After serving on a voluntary basis, Watson became director of Cold Spring Harbor Laboratory on Long Island in 1976. It had once been a whaling village, and the humble buildings retained a rustic charm, though when Watson arrived the rustic quality was on a steep descent toward ruination. Its endowment was virtually nonexistent and money was so tight a former director mowed the lawn himself.

As skilled at raising money as he was at solving difficult scientific problems, Watson turned the institution into a major research center that helped reveal the role of genetics in cancer. By 2019, the endowment had grown to $670 million, and the research staff had tripled. From an annual budget of $1 million, it had grown to $190 million.

“You have to like people who have money,” Watson said in explanation of his success at resurrecting Cold Spring Harbor. “I really like rich people.” His growing eccentricity, which included untied shoelaces and hair that spiked out in all directions, completed the stock image of a distracted scientist. Acquaintances swore they saw him untie his shoelaces before meeting with a potential donor.

In 1988, he became the first director of the $3-billion Human Genome Project, whose goal was to identify and map every human gene. He resigned four years later, after a public falling-out with the director of the National Institutes of Health. “I completely failed the test,” he said of his experience as a bureaucrat.

Among his passions were tennis and charity work. In 2014, the year of the documentary that sealed his fate as an exile, Watson put his Nobel gold medal up for auction. He gave away virtually all the $4.1 million it fetched. The buyer, Russian billionaire Alisher Usmanov, returned it a year later, saying he felt bad the scientist had to sell possessions to support worthy causes.

A complex, beguiling, maddening man who defied easy, or any, categorization, Watson followed his own star to the end of his life, insisting in 2016, when he was nearly 90, that he didn’t want to die until a cure for cancer was found. At the time, he was still playing tennis three times a week, with partners decades younger.

Besides the Nobel Prize, Watson was awarded the Presidential Medal of Freedom, the Eli Lilly Award in Biochemistry and the Albert Lasker Award for Basic Medical Research. He was a member of the American Academy of Arts and Sciences, the National Academy of Sciences, and was made an honorary Knight of the British Empire. Among his literary works were both scientific and popular books, from “Recombinant DNA” to “Genes, Girls, and Gamow,” a typically cheeky book recounting his twin obsessions, scientific glory and the opposite sex.

Johnson is a former Times staff writer.