This article is part of Overlooked, a series of obituaries about remarkable people whose deaths, beginning in 1851, went unreported in The Times.

Katharine Dexter McCormick, who was born to a life of wealth, which she compounded through marriage, could have sat back and simply enjoyed the many advantages that flowed her way. Instead, she put her considerable fortune — matched by her considerable willfulness — into making life better for women.

An activist, philanthropist and benefactor, McCormick used her wealth strategically, most notably to underwrite the basic research that led to the development of the birth control pill in the late 1950s.

Before then, contraception in the United States was extremely limited, with bans on diaphragms and condoms. The advent of the pill made it easier for women to plan when and whether to have children, and it fueled the explosive sexual revolution of the 1960s. Today, the pill, despite some side effects, is the most widely used form of reversible contraception in the United States.

McCormick’s interest in birth control began in the 1910s, when she learned of Margaret Sanger, the feminist leader who had been jailed for opening the nation’s first birth control clinic. She shared Sanger’s fervent belief that women should be able to chart their own biological destinies.

The two met in 1917 and soon hatched an elaborate scheme to smuggle diaphragms into the United States.

Diaphragms had been banned under the Comstock Act of 1873, which made it a federal crime to send or deliver through the mail “obscene, lewd or lascivious” material — including pornography, contraceptives and items used for abortions. (The law, which still prohibits mailing items related to abortions, has received renewed attention since the federal right to abortion was overturned in 2022.)

McCormick, who was fluent in French and German, traveled to Europe, where diaphragms were in common use. She had studied biology at the Massachusetts Institute of Technology and was able to pose as a scientist in meetings with diaphragm manufacturers. “She purchased hundreds of the devices and hired local seamstresses to sew them into dresses, evening gowns and coats,” according to a 2011 article in M.I.T. Technology Review. “Then she had the garments wrapped and packed neatly into trunks for shipment.”

She and her steamer trunks made it through customs. If the authorities had stopped her, the article said, they would have found “nothing but slightly puffy dresses in the possession of a bossy socialite, a woman oozing such self-importance and tipping her porters so grandly that no one suspected a thing.”

From 1922 to 1925, McCormick smuggled more than 1,000 diaphragms into Sanger’s clinics.

After her husband died in 1947, she inherited a considerable amount of money, and she asked Sanger for advice on how to put it to use advancing research into contraception. In 1953, Sanger introduced her to Gregory Goodwin Pincus and Min-Chueh Chang, researchers at the Worcester Foundation for Experimental Biology in Massachusetts, who were trying to develop a safe, reliable oral contraceptive.

She was excited by their work and provided almost all the funding — $2 million (about $23 million today) — required to develop the pill. She even moved to Worcester to monitor and encourage their research. Pincus’s wife, Elizabeth, described McCormick as a warrior: “Little old woman she was not. She was a grenadier.”

The Food and Drug Administration approved the pill for birth control in 1960.

Katharine Moore Dexter was born into an affluent, socially activist family on Aug. 27, 1875, in Dexter, Mich., west of Detroit. The town was named for her grandfather, Samuel W. Dexter, who founded it in 1824 and maintained an Underground Railroad stop in his home, where Katharine was born; her great-grandfather, Samuel Dexter, was Treasury secretary under President John Adams.

Katharine and her older brother, Samuel T. Dexter, grew up in Chicago. Their mother, Josephine (Moore) Dexter, was a Boston Brahmin who supported women’s rights. Their father, Wirt Dexter, was a high-powered lawyer who served as president of the Chicago Bar Association and as a director of the Chicago, Burlington & Quincy Railroad. He also headed the relief committee after the Great Chicago Fire of 1871 and was a major real estate developer.

He died when Katharine was 14. A few years later, her brother died of meningitis while attending Harvard Law School. Those early deaths pointed her toward a career in medicine.

She attended M.I.T. and majored in biology, rare achievements for a woman of that era. She arrived with a mind of her own, and successfully challenged a rule that female students had to wear hats at all times, arguing that they posed a fire hazard in the science labs. She graduated in 1904 and planned to attend medical school.

But by then, she had started dating the dashing Stanley Robert McCormick, whom she had known in Chicago and who was an heir to an immense fortune built on a mechanical harvesting machine that his father had invented. As a young lawyer, he helped negotiate a merger that made his family a major owner of International Harvester; by 1909, it was the fourth largest industrial company in America, measured in assets.

McCormick persuaded Katharine to marry him instead of going to medical school. They wed at her mother’s château in Switzerland and settled in Brookline, Mass.

But even before they married, he had showed signs of mental instability, and he began experiencing violent, paranoid delusions. He was hospitalized with what was later determined to be schizophrenia, and remained under psychiatric care — mostly at Riven Rock, the McCormick family estate in Montecito, Calif. — until his death. She never divorced him and never remarried. They had no children.

Katharine McCormick spent decades mired in personal, medical and legal disputes with her husband’s siblings. They battled over his treatment, his guardianship and eventually his estate, as detailed in a 2007 article in Prologue Magazine, a publication of the National Archives. She was his sole beneficiary, inheriting about $40 million ($563 million in today’s dollars). Combined with the $10 million (more than $222 million today) she had inherited from her mother, that made her one of the wealthiest women in America.

As her husband’s illness consumed her personal life, McCormick threw herself into social causes. She contributed financially to the suffrage movement, gave speeches and rose in leadership to become treasurer and vice president of the National American Woman Suffrage Association. After women won the right to vote in 1920, the association evolved into the League of Women Voters; McCormick became its vice president.

In 1927, she established the Neuroendocrine Research Foundation at Harvard Medical School, believing that a malfunctioning adrenal gland was responsible for her husband’s schizophrenia. She provided funding for two decades and acquired an expertise in endocrinology that later informed her interest in the development of an oral contraceptive.

After the F.D.A. approved the pill, McCormick turned her attention to funding the first on-campus residence for women at M.I.T. When she studied there, women had no housing, one of several factors that discouraged them from applying. “I believe if we can get them properly housed,” she said, “that the best scientific education in our country will be open to them permanently.”

McCormick Hall, named for her husband, opened on the institute’s Cambridge campus in 1963. At the time, women made up about 3 percent of the school’s undergraduates; today, they make up about 50 percent.

By the time she died of a stroke on Dec. 28, 1967, at her home in Boston, McCormick had played a major role in expanding opportunities for women in the 20th century. She was 92.

Apart from a short article in The Boston Globe, her death drew little notice. The later obituaries of the birth-control researchers she had supported did not mention her role in their achievement.

In her will, she left $5 million to the Planned Parenthood Federation (more than $46 million today) and $1 million to Pincus’s laboratories (more than $9 million today). Earlier, she had donated her inherited property in Switzerland to the U.S. government for use by its diplomatic mission in Geneva. She left most of the rest of her estate to M.I.T.