In 1960, Simões-Ferreira earned a Bachelor of Arts in Romance Languages and Literature from the University of the Witwatersrand, Johannesburg, South Africa. In 1963, she graduated from the School of Translation and Interpretation at the University of Geneva and moved to the United States to be an interpreter at the United Nations.

On February 5, 1966, at Pittsburgh, Pennsylvania’s gothic Heinz Chapel on the campus of the University of Pittsburgh, Simões-Ferreira married future U.S. Senator John Heinz, an heir to the H. J. Heinz Company. In 1971, Teresa Heinz became a naturalized United States citizen. The couple had three sons:

In 1990, Teresa Heinz met Senator Kerry at an Earth Day rally. This was the only reported time the two met before Senator Heinz died in a plane crash on April 4, 1991. In 1992, Teresa Heinz met Kerry again, this time at the Earth Summit in Rio de Janeiro, Brazil. Heinz was a member of a State Department delegation appointed by then-President George H. W. Bush. The two began courting in 1993 and were married May 26, 1995, in Nantucket, Massachusetts. Choosing to remain registered as a Republican until John Kerry’s presidential bid in 2004, Heinz retained the name Teresa Heinz. In May 2004, she said:

Heinz has contributed to the environmental movement through many programs and outreach efforts. In 1990, she co-founded the Alliance to End Childhood Lead Poisoning (later known as the Alliance for Healthy Homes, it has since merged with the National Center for Healthy Housing), through the first environmental grant of the Vira I. Heinz Endowment. In 1992, she was a Delegate to the Earth Summit, representing Non-Governmental Organizations.

In 1993, with Kerry and environmentalist academic Dr. Anthony Cortese, she co-founded Second Nature, which brings “Education for Sustainability” to college campuses. In 1993, she founded the Heinz Awards, including a category for Outstanding Contributions to the Environment. In 1995, with a $20 million grant, the Heinz Endowments provided initial funding for The Heinz Center, “a nonprofit institution dedicated to improving the scientific and economic foundation for environmental policy through multisectoral collaboration among industry, government, academia, and environmental organizations.”

In 1995, the book Pensions in Crisis: Why the system is failing America and how you can protect your future (later republished as The Pension Book) was published, with support from the Teresa and H. John Heinz III Foundation, and a foreword by Heinz.

Since 1996, Heinz has hosted an annual “Women’s Health and the Environment” conference series. She founded Teresa Heinz Scholars for Environmental Research, which annually awards eight $10,000 awards for doctoral dissertation support and eight $5,000 awards for Masters’ thesis support for research having “public policy relevance that increases society’s understanding of environmental concerns and proposed solutions.” Heinz is a board member of the Environmental Defense Fund.

In 1996, the Heinz Foundations created WISER, the Women’s Institute for a Secure Retirement.

In 2003, Heinz was awarded the Albert Schweitzer Gold Medal for Humanitarianism. She has been elected a Fellow of the American Academy of Arts and Sciences. She has been a Trustee of the St. Paul’s School (Concord, New Hampshire), which Kerry attended.

Like her first husband, Heinz was a registered Republican for most of her voting life, and she remained a registered Republican despite being married to Kerry. In January 2003, she changed her registration to the Democratic Party.

In 2003, Heinz was named to the PoliticsPA list of “Pennsylvania’s Most Politically Powerful Women”.

Heinz has a reputation in the media as a very direct personality. In an interview published in USA Today in July 2004, Heinz was asked about the differences between then-First Lady Laura Bush and herself:

Heinz is said to have been encouraged to run for her first husband’s vacant Senate seat after his death. Heinz declined and refused to endorse Republican Congressman Rick Santorum’s 1994 bid for the seat. She publicly denounced him as the “antithesis” of her late husband, and later called him “Forrest Gump with attitude.” It was rumored she would challenge Santorum in 2006 (as a Democrat), but she did not enter the race, and the Democratic nomination went to State Treasurer Bob Casey, Jr., who went on to defeat Santorum.

In December 2009, Heinz revealed that she was being treated for breast cancer. Heinz indicated that she had undergone several lumpectomies and would be following up with a targeted type of radiation therapy treatment called accelerated partial breast irradiation (APBI).

On July 7, 2013, Heinz was taken by ambulance to Nantucket Cottage Hospital after showing symptoms consistent with a seizure. She was described as being in “critical but stable” condition. Heinz was then flown to Massachusetts General Hospital for further medical treatment and tests. Her condition was upgraded to fair the next day, and doctors were able to rule out a heart attack, brain tumor, stroke, and other triggers. On July 11, she was transferred to Spaulding Rehabilitation Hospital to continue her recovery. Heinz was released on July 17, 2013, from Spaulding Rehabilitation Hospital in Boston. She recovered at home after some limited out-patient treatment.